125-624: The Ythan Estuary is the tidal component of the Ythan River , emptying into the North Sea 19 kilometres (12 mi) north of Aberdeen , Scotland. The estuary ’s tidal action extends a 7 kilometres (4.3 mi) inland and has characteristic widths of between 250 metres (820 ft) and 780 metres (2,560 ft). Besides the tidal channel there are interfaces to the upland dunes including mudflats , sand beaches and shingle flats . Reaches of salt marsh occur, but they are primarily near
250-445: A Stone Age settlement. Some of the dunes north of the estuary rise to a height of about 80 metres (260 ft) and the lower ones to the south of the estuary rise to about 50 metres (160 ft) in height. Proceeding from the mouth the estuary inland, there are initially beach sands at the margin, thence shingle beach and mudflats. Quickly, by the time of reaching the first roadway bridge crossing about 1,300 metres (4,300 ft) up
375-677: A day were similar, but at springs the tides rose 7 feet (2.1 m) in the morning but 9 feet (2.7 m) in the evening. Pierre-Simon Laplace formulated a system of partial differential equations relating the ocean's horizontal flow to its surface height, the first major dynamic theory for water tides. The Laplace tidal equations are still in use today. William Thomson, 1st Baron Kelvin , rewrote Laplace's equations in terms of vorticity which allowed for solutions describing tidally driven coastally trapped waves, known as Kelvin waves . Others including Kelvin and Henri Poincaré further developed Laplace's theory. Based on these developments and
500-523: A few days after (or before) new and full moon and are highest around the equinoxes, though Pliny noted many relationships now regarded as fanciful. In his Geography , Strabo described tides in the Persian Gulf having their greatest range when the moon was furthest from the plane of the Equator. All this despite the relatively small amplitude of Mediterranean basin tides. (The strong currents through
625-473: A few kilometres north along the coast is the only place name associated with Viking landings, Saint Olaf at Cruden Bay . There are several distinct habitats within the Ythan Estuary complex including marsh, littoral , estuarine , lacustrine and dunes. Thus there is an unusual diversity of flora and fauna present in this nature reserve . The estuary itself is tidal, located seven kilometres from
750-623: A fierce and powerful people and were often in conflict with the Vikings. To counter the Saxon aggression and solidify their own presence, the Danes constructed the huge defence fortification of Danevirke in and around Hedeby . The Vikings witnessed the violent subduing of the Saxons by Charlemagne , in the thirty-year Saxon Wars of 772–804. The Saxon defeat resulted in their forced christening and
875-505: A given day are typically not the same height (the daily inequality); these are the higher high water and the lower high water in tide tables . Similarly, the two low waters each day are the higher low water and the lower low water . The daily inequality is not consistent and is generally small when the Moon is over the Equator . The following reference tide levels can be defined, from
1000-552: A medieval Swedish law, the Västgötalagen , from Västergötland declared no-one could inherit while staying in "Greece"—the then Scandinavian term for the Byzantine Empire—to stop the emigration, especially as two other European courts simultaneously also recruited Scandinavians: Kievan Rus' c. 980–1060 and London 1018–1066 (the Þingalið ). There is archaeological evidence that Vikings reached Baghdad ,
1125-502: A pool of unmarried men who are willing to engage in risky status-elevating and sex-seeking behaviors. The Annals of Ulster states that in 821 the Vikings plundered an Irish village and "carried off a great number of women into captivity". One common theory posits that Charlemagne "used force and terror to Christianise all pagans", leading to baptism, conversion or execution, and as a result, Vikings and other pagans resisted and wanted revenge. Professor Rudolf Simek states that "it
1250-617: A shortage of women available to the Viking male. Consequently, the average Viking man may have felt compelled to seek wealth and power to have the means to acquire suitable women. Several centuries after Dudo's observations, scholars revived this idea, and over time it became a cliché among scholars of the Viking Age. Viking men would often buy or capture women and make them into their wives or concubines; such polygynous marriages increase male-male competition in society because they create
1375-516: A smooth sphere covered by a sufficiently deep ocean under the tidal force of a single deforming body is a prolate spheroid (essentially a three-dimensional oval) with major axis directed toward the deforming body. Maclaurin was the first to write about the Earth's rotational effects on motion. Euler realized that the tidal force's horizontal component (more than the vertical) drives the tide. In 1744 Jean le Rond d'Alembert studied tidal equations for
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#17327582074821500-526: A system of pulleys to add together six harmonic time functions. It was "programmed" by resetting gears and chains to adjust phasing and amplitudes. Similar machines were used until the 1960s. The first known sea-level record of an entire spring–neap cycle was made in 1831 on the Navy Dock in the Thames Estuary . Many large ports had automatic tide gauge stations by 1850. John Lubbock was one of
1625-549: A wildfowling code of conduct with a voluntary refuge area south of the main bridge over the estuary (A975). Visitors can fish for estuarine species such as flounder for free but are advised not to disturb birds during the breeding season. Game fisher's catching salmon and sea trout is by permit only. North of the estuary mouth extend the Sands of Forvie , the most extensive sand dune formation in Europe, which has been shown to have been
1750-431: Is "clear evidence" that it was used as a synonym, while Eric Christiansen avers that it is a mistranslation made at the insistence of the publisher. The word wicing does not occur in any preserved Middle English texts. The word Viking was introduced into Modern English during the 18th-century Viking revival, at which point it acquired romanticised heroic overtones of "barbarian warrior" or noble savage . During
1875-575: Is a group of about 30 runestones in Sweden which refer to Viking Age voyages to England. They constitute one of the largest groups of runestones that mention voyages to other countries, and they are comparable in number only to the approximately 30 Greece Runestones and the 26 Ingvar Runestones , the latter referring to a Viking expedition to the Middle East. They were engraved in Old Norse with
2000-455: Is a useful concept. Tidal stage is also measured in degrees, with 360° per tidal cycle. Lines of constant tidal phase are called cotidal lines , which are analogous to contour lines of constant altitude on topographical maps , and when plotted form a cotidal map or cotidal chart . High water is reached simultaneously along the cotidal lines extending from the coast out into the ocean, and cotidal lines (and hence tidal phases) advance along
2125-422: Is at once cotidal with high and low waters, which is satisfied by zero tidal motion. (The rare exception occurs when the tide encircles an island, as it does around New Zealand, Iceland and Madagascar .) Tidal motion generally lessens moving away from continental coasts, so that crossing the cotidal lines are contours of constant amplitude (half the distance between high and low water) which decrease to zero at
2250-659: Is better attested linguistically, and the term most likely predates the use of the sail by the Germanic peoples of northwestern Europe. In the Middle Ages, viking came to refer to Scandinavian pirates or raiders. The earliest reference to wicing in English sources is from the Épinal-Erfurt glossary ( c. 700 ), about 93 years before the first known attack by Viking raiders in England. The glossary lists
2375-457: Is called the spring tide . It is not named after the season , but, like that word, derives from the meaning "jump, burst forth, rise", as in a natural spring . Spring tides are sometimes referred to as syzygy tides . When the Moon is at first quarter or third quarter, the Sun and Moon are separated by 90° when viewed from the Earth (in quadrature ), and the solar tidal force partially cancels
2500-446: Is never time for the fluid to "catch up" to the state it would eventually reach if the tidal force were constant—the changing tidal force nonetheless causes rhythmic changes in sea surface height. When there are two high tides each day with different heights (and two low tides also of different heights), the pattern is called a mixed semi-diurnal tide . The changing distance separating the Moon and Earth also affects tide heights. When
2625-525: Is not a coincidence if the early Viking activity occurred during the reign of Charlemagne". The ascendance of Christianity in Scandinavia led to serious conflict, dividing Norway for almost a century. However, this time period did not commence until the 10th century. Norway was never subject to aggression by Charlemagne and the period of strife was due to successive Norwegian kings embracing Christianity after encountering it overseas. Another explanation
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#17327582074822750-408: Is not necessarily when the Moon is nearest to zenith or nadir , but the period of the forcing still determines the time between high tides. Because the gravitational field created by the Moon weakens with distance from the Moon, it exerts a slightly stronger than average force on the side of the Earth facing the Moon, and a slightly weaker force on the opposite side. The Moon thus tends to "stretch"
2875-461: Is not the case due to the free fall of the whole Earth, not only the oceans, towards these bodies) a different pattern of tidal forces would be observed, e.g. with a much stronger influence from the Sun than from the Moon: The solar gravitational force on the Earth is on average 179 times stronger than the lunar, but because the Sun is on average 389 times farther from the Earth, its field gradient
3000-402: Is shorter than average, and stronger tidal currents than average. Neaps result in less extreme tidal conditions. There is about a seven-day interval between springs and neaps. Tidal constituents are the net result of multiple influences impacting tidal changes over certain periods of time. Primary constituents include the Earth's rotation, the position of the Moon and Sun relative to the Earth,
3125-582: Is taken to have been the period from the earliest recorded raids by Norsemen in 793 until the Norman conquest of England in 1066. Vikings used the Norwegian Sea and Baltic Sea for sea routes to the south. The Normans were descendants of those Vikings who had been given feudal overlordship of areas in northern France, namely the Duchy of Normandy , in the 10th century. In that respect, descendants of
3250-407: Is that the Vikings exploited a moment of weakness in the surrounding regions. Contrary to Simek's assertion, Viking raids occurred sporadically long before the reign of Charlemagne; but exploded in frequency and size after his death, when his empire fragmented into multiple much weaker entities. England suffered from internal divisions and was a relatively easy prey given the proximity of many towns to
3375-419: Is the time required for the Earth to rotate once relative to the Moon. Simple tide clocks track this constituent. The lunar day is longer than the Earth day because the Moon orbits in the same direction the Earth spins. This is analogous to the minute hand on a watch crossing the hour hand at 12:00 and then again at about 1: 05 + 1 ⁄ 2 (not at 1:00). The Moon orbits the Earth in the same direction as
3500-705: Is weaker. The overall proportionality is Viking Chronological history Vikings were seafaring people originally from Scandinavia (present-day Denmark , Norway , and Sweden ), who from the late 8th to the late 11th centuries raided, pirated, traded, and settled throughout parts of Europe. They also voyaged as far as the Mediterranean , North Africa , the Middle East , Greenland , and Vinland (present-day Newfoundland in Canada , North America ). In their countries of origin, and some of
3625-689: The British Isles , the Faroe Islands , Iceland , Greenland , Normandy , and the Baltic coast , as well as along the Dnieper and Volga trade routes across modern-day Russia, Belarus , and Ukraine , where they were also known as Varangians . The Normans , Norse-Gaels , Rus' people , Faroese , and Icelanders emerged from these Norse colonies. At one point, a group of Rus Vikings went so far south that, after briefly being bodyguards for
3750-606: The Coriolis effect , is generally clockwise in the southern hemisphere and counterclockwise in the northern hemisphere. The difference of cotidal phase from the phase of a reference tide is the epoch . The reference tide is the hypothetical constituent "equilibrium tide" on a landless Earth measured at 0° longitude, the Greenwich meridian. In the North Atlantic, because the cotidal lines circulate counterclockwise around
3875-691: The Danelaw , including Scandinavian York, the administrative centre of the remains of the Kingdom of Northumbria , parts of Mercia , and East Anglia . Viking navigators opened the road to new lands to the north, west and east, resulting in the foundation of independent settlements in the Shetland , Orkney , and Faroe Islands; Iceland; Greenland ; and L'Anse aux Meadows , a short-lived settlement in Newfoundland , circa 1000. The Greenland settlement
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4000-534: The Earth and Moon orbiting one another. Tide tables can be used for any given locale to find the predicted times and amplitude (or " tidal range "). The predictions are influenced by many factors including the alignment of the Sun and Moon, the phase and amplitude of the tide (pattern of tides in the deep ocean), the amphidromic systems of the oceans, and the shape of the coastline and near-shore bathymetry (see Timing ). They are however only predictions,
4125-722: The Euripus Strait and the Strait of Messina puzzled Aristotle .) Philostratus discussed tides in Book Five of The Life of Apollonius of Tyana . Philostratus mentions the moon, but attributes tides to "spirits". In Europe around 730 AD, the Venerable Bede described how the rising tide on one coast of the British Isles coincided with the fall on the other and described the time progression of high water along
4250-474: The North Sea . Much later, in the late 20th century, geologists noticed tidal rhythmites , which document the occurrence of ancient tides in the geological record, notably in the Carboniferous . The tidal force produced by a massive object (Moon, hereafter) on a small particle located on or in an extensive body (Earth, hereafter) is the vector difference between the gravitational force exerted by
4375-473: The North Sea . In the estuary and its verges, the presence of tern colonies is notable, since there are several distinct species that utilize the north banks of the Ythan Estuary, and comprise a percentage of the breeding pairs of terns in the United Kingdom. In the summer terns can be observed feeding in their characteristic diving patterns approximately 600 to 900 metres inland from the estuary. At
4500-512: The Ramsar list of wetlands of international importance with Meikle Loch . There are 50 breeding pairs of common shelducks in the estuary, and there is a mixed tern breeding colony on the east shore 1 kilometre (3,300 ft) from the mouth comprising Arctic , Sandwich , little and common terns . Leisure activities including birdwatching, fishing, canoeing and wildfowling are permitted. There are hides to watch waders (best at low tide), and
4625-512: The Slavic languages in the Viking settlements of Eastern Europe. It has been speculated that the reason for this was the great differences between the two languages, combined with the Rus Vikings' more peaceful businesses in these areas, and the fact that they were outnumbered. The Norse named some of the rapids on the Dnieper , but this can hardly be seen from modern names. The Norse of
4750-598: The Younger Futhark . The Jelling stones date from between 960 and 985. The older, smaller stone was raised by King Gorm the Old , the last pagan king of Denmark, as a memorial honouring Queen Thyre . The larger stone was raised by his son, Harald Bluetooth , to celebrate the conquest of Denmark and Norway and the conversion of the Danes to Christianity. It has three sides: one with an animal image; one with an image of
4875-440: The lunar theory of E W Brown describing the motions of the Moon, Arthur Thomas Doodson developed and published in 1921 the first modern development of the tide-generating potential in harmonic form: Doodson distinguished 388 tidal frequencies. Some of his methods remain in use. From ancient times, tidal observation and discussion has increased in sophistication, first marking the daily recurrence, then tides' relationship to
5000-578: The lunitidal interval . To make accurate records, tide gauges at fixed stations measure water level over time. Gauges ignore variations caused by waves with periods shorter than minutes. These data are compared to the reference (or datum) level usually called mean sea level . While tides are usually the largest source of short-term sea-level fluctuations, sea levels are also subject to change from thermal expansion , wind, and barometric pressure changes, resulting in storm surges , especially in shallow seas and near coasts. Tidal phenomena are not limited to
5125-642: The 10th and 11th centuries, the exposed family trees, the self-images, and the ethical values that are contained in these literary writings. Indirectly, the Vikings have also left a window open onto their language, culture and activities, through many Old Norse place names and words found in their former sphere of influence. Some of these place names and words are still in direct use today, almost unchanged, and shed light on where they settled and what specific places meant to them. Examples include place names like Egilsay (from Eigils ey meaning Eigil's Island), Ormskirk (from Ormr kirkja meaning Orms Church or Church of
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5250-516: The 12th through 14th centuries, and many traditions connected with the Viking Age were written down for the first time in the Icelandic sagas . A literal interpretation of these medieval prose narratives about the Vikings and the Scandinavian past is doubtful, but many specific elements remain worthy of consideration, such as the great quantity of skaldic poetry attributed to court poets of
5375-653: The 20th century, the meaning of the term was expanded to refer not only to seaborne raiders from Scandinavia and other places settled by them (like Iceland and the Faroe Islands ), but also any member of the culture that produced the raiders during the period from the late 8th to the mid-11th centuries, or more loosely from about 700 to as late as about 1100. As an adjective, the word is used to refer to ideas, phenomena, or artefacts connected with those people and their cultural life, producing expressions like Viking age , Viking culture , Viking art , Viking religion , Viking ship and so on. The Viking Age in Scandinavian history
5500-555: The 7th century had also affected trade with Western Europe. Raids in Europe, including raids and settlements from Scandinavia, were not unprecedented and had occurred long before the Vikings arrived. The Jutes invaded the British Isles three centuries earlier, from Jutland during the Age of Migrations , before the Danes settled there. The Saxons and the Angles did the same, embarking from mainland Europe. The Viking raids were, however,
5625-457: The 960s and 1043. Its inhabitants were known as Jomsvikings . Jomsborg's exact location, or its existence, has not yet been established, though it is often maintained that Jomsborg was somewhere on the islands of the Oder estuary. While the Vikings were active beyond their Scandinavian homelands, Scandinavia was itself experiencing new influences and undergoing a variety of cultural changes. By
5750-560: The Byzantine emperor, they attacked the Byzantine city of Constantinople . Vikings also voyaged to Iran and Arabia . They were the first Europeans to reach North America, briefly settling in Newfoundland (Vinland). While spreading Norse culture to foreign lands, they simultaneously brought home slaves, concubines, and foreign cultural influences to Scandinavia, influencing the genetic and historical development of both. During
5875-589: The EU Directive by sustaining the following winter migratory species population of European significance: 57°20′30″N 01°57′30″W / 57.34167°N 1.95833°W / 57.34167; -1.95833 Tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun ) and are also caused by
6000-426: The Earth rotates on its axis, so it takes slightly more than a day—about 24 hours and 50 minutes—for the Moon to return to the same location in the sky. During this time, it has passed overhead ( culmination ) once and underfoot once (at an hour angle of 00:00 and 12:00 respectively), so in many places the period of strongest tidal forcing is the above-mentioned, about 12 hours and 25 minutes. The moment of highest tide
6125-419: The Earth slightly along the line connecting the two bodies. The solid Earth deforms a bit, but ocean water, being fluid, is free to move much more in response to the tidal force, particularly horizontally (see equilibrium tide ). As the Earth rotates, the magnitude and direction of the tidal force at any particular point on the Earth's surface change constantly; although the ocean never reaches equilibrium—there
6250-586: The Earth's accumulated dynamic tidal response to the applied forces, which response is influenced by ocean depth, the Earth's rotation, and other factors. In 1740, the Académie Royale des Sciences in Paris offered a prize for the best theoretical essay on tides. Daniel Bernoulli , Leonhard Euler , Colin Maclaurin and Antoine Cavalleri shared the prize. Maclaurin used Newton's theory to show that
6375-649: The Forvie Moor element of the Ythan Estuary complex, both mute and whooper swans occur. Meikle Loch is an element of the Ythan Estuary complex and sustains some aquatic vegetation , and from November to March is home to many wading birds, ducks and geese. Based upon Articles 4.1 and 4.2 of the European Union Directive 79/409/EEC this site qualifies as a Special Protection Area (SPA) by supporting biota populations of European importance. The component landforms which are considered elements of
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#17327582074826500-540: The Latin alphabet. The runestones are unevenly distributed in Scandinavia: Denmark has 250 runestones, Norway has 50 while Iceland has none. Sweden has as many as between 1,700 and 2,500 depending on the definition. The Swedish district of Uppland has the highest concentration with as many as 1,196 inscriptions in stone, whereas Södermanland is second with 391. The majority of runic inscriptions from
6625-611: The Latin translation for wicing as piraticum 'pirate'. In Old English , the word wicing appears in the Anglo-Saxon poem Widsith , probably from the 9th century. The word was not regarded as a reference to nationality, with other terms such as Northmen and Dene 'Danes' being used for that. In Asser 's Latin work The Life of King Alfred , the Danes are referred to as pagani 'pagans'; historian Janet Nelson states that pagani became "the Vikings" in standard translations of this work, even though there
6750-427: The Moon and its phases. Bede starts by noting that the tides rise and fall 4/5 of an hour later each day, just as the Moon rises and sets 4/5 of an hour later. He goes on to emphasise that in two lunar months (59 days) the Moon circles the Earth 57 times and there are 114 tides. Bede then observes that the height of tides varies over the month. Increasing tides are called malinae and decreasing tides ledones and that
6875-459: The Moon is closest, at perigee , the range increases, and when it is at apogee , the range shrinks. Six or eight times a year perigee coincides with either a new or full moon causing perigean spring tides with the largest tidal range . The difference between the height of a tide at perigean spring tide and the spring tide when the moon is at apogee depends on location but can be large as a foot higher. These include solar gravitational effects,
7000-462: The Moon on the particle, and the gravitational force that would be exerted on the particle if it were located at the Earth's center of mass. Whereas the gravitational force subjected by a celestial body on Earth varies inversely as the square of its distance to the Earth, the maximal tidal force varies inversely as, approximately, the cube of this distance. If the tidal force caused by each body were instead equal to its full gravitational force (which
7125-457: The Moon's altitude (elevation) above the Earth's Equator, and bathymetry . Variations with periods of less than half a day are called harmonic constituents . Conversely, cycles of days, months, or years are referred to as long period constituents. Tidal forces affect the entire earth , but the movement of solid Earth occurs by mere centimeters. In contrast, the atmosphere is much more fluid and compressible so its surface moves by kilometers, in
7250-449: The Moon's tidal force. At these points in the lunar cycle, the tide's range is at its minimum; this is called the neap tide , or neaps . "Neap" is an Anglo-Saxon word meaning "without the power", as in forðganges nip (forth-going without-the-power). Neap tides are sometimes referred to as quadrature tides . Spring tides result in high waters that are higher than average, low waters that are lower than average, " slack water " time that
7375-449: The Moon. Abu Ma'shar discussed the effects of wind and Moon's phases relative to the Sun on the tides. In the 12th century, al-Bitruji (d. circa 1204) contributed the notion that the tides were caused by the general circulation of the heavens. Simon Stevin , in his 1608 De spiegheling der Ebbenvloet ( The theory of ebb and flood ), dismissed a large number of misconceptions that still existed about ebb and flood. Stevin pleaded for
7500-573: The Norsemen settled in the present-day Faroe Islands , Iceland , Norse Greenland , Newfoundland , the Netherlands , Germany, Normandy , Italy, Scotland , England, Wales , Ireland, the Isle of Man , Estonia , Latvia , Lithuania , Ukraine , Russia and Turkey, as well as initiating the consolidation that resulted in the formation of the present-day Scandinavian countries. In the Viking Age,
7625-467: The North and Irish Seas diminished markedly. The kings of Norway continued to assert power in parts of northern Britain and Ireland, and raids continued into the 12th century, but the military ambitions of Scandinavian rulers were now directed toward new paths. In 1107, Sigurd I of Norway sailed for the eastern Mediterranean with Norwegian crusaders to fight for the newly established Kingdom of Jerusalem ;
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#17327582074827750-684: The Northumbrian coast. The first tide table in China was recorded in 1056 AD primarily for visitors wishing to see the famous tidal bore in the Qiantang River . The first known British tide table is thought to be that of John Wallingford, who died Abbot of St. Albans in 1213, based on high water occurring 48 minutes later each day, and three hours earlier at the Thames mouth than upriver at London . In 1614 Claude d'Abbeville published
7875-584: The Obotrite city of Reric on the southern Baltic coast in 808 AD and transferred the merchants and traders to Hedeby. This secured Viking supremacy in the Baltic Sea, which continued throughout the Viking Age. Because of the expansion of the Vikings across Europe, a comparison of DNA and archeology undertaken by scientists at the University of Cambridge and University of Copenhagen suggested that
8000-642: The Old Norse of the Vikings and give an opportunity to understand their interactions with the people and cultures of the British Isles. In the Northern Isles of Shetland and Orkney, Old Norse completely replaced the local languages and over time evolved into the now extinct Norn language . Some modern words and names only emerge and contribute to our understanding after a more intense research of linguistic sources from medieval or later records, such as York (Horse Bay), Swansea ( Sveinn 's Isle) or some of
8125-585: The Red , reached North America and set up short-lived settlements in present-day L'Anse aux Meadows , Newfoundland, Canada. This expansion occurred during the Medieval Warm Period . Viking expansion into continental Europe was limited. Their realm was bordered by powerful tribes to the south. Early on, it was the Saxons who occupied Old Saxony , located in what is now Northern Germany. The Saxons were
8250-470: The SPA or SSSI are the estuary itself, the dunes to the east known as the Sands of Forvie , Meikle Loch and the adjacent Kippet Hills. The Ythan Estuary SPA code is UK9002221, which designation was conveyed on 30 March 1998. Per Article 4.1, Annex I, the Ythan Estuary complex supports the following significant bird populations during the breeding season: The Ythan Estuary also is qualified per Article 4.2 of
8375-469: The Sun and moon. Pytheas travelled to the British Isles about 325 BC and seems to be the first to have related spring tides to the phase of the moon. In the 2nd century BC, the Hellenistic astronomer Seleucus of Seleucia correctly described the phenomenon of tides in order to support his heliocentric theory. He correctly theorized that tides were caused by the moon , although he believed that
8500-571: The Swedes, Eric , was married to Gunhild , of the Polish House of Piast . Likewise, his son, Olof , fell in love with Edla , a Slavic woman, and took her as his frilla (concubine). They had a son and a daughter: Emund the Old , King of Sweden, and Astrid , Queen of Norway. Cnut the Great , King of Denmark, England and Norway, was the son of a daughter of Mieszko I of Poland , possibly
8625-403: The Two Chief World Systems , whose working title was Dialogue on the Tides , gave an explanation of the tides. The resulting theory, however, was incorrect as he attributed the tides to the sloshing of water caused by the Earth's movement around the Sun. He hoped to provide mechanical proof of the Earth's movement. The value of his tidal theory is disputed. Galileo rejected Kepler's explanation of
8750-446: The University of Bonn, posits that the presence of Slavs in Scandinavia is "more significant than previously thought", while Mats Roslund states that "the Slavs and their interaction with Scandinavia have not been adequately investigated". A 10th-century grave of a warrior-woman in Denmark was long thought to belong to a Viking. However, new analyses suggest that the woman may have been a Slav from present-day Poland. The first king of
8875-424: The Viking Age could read and write and used a non-standardised alphabet, called runor , built upon sound values. While there are few remains of runic writing on paper from the Viking era, thousands of stones with runic inscriptions have been found where Vikings lived. They are usually in memory of the dead, though not necessarily placed at graves. The use of runor survived into the 15th century, used in parallel with
9000-504: The Viking Age, the Norse homelands were gradually consolidated from smaller kingdoms into three larger kingdoms: Denmark, Norway, and Sweden. The Vikings spoke Old Norse and made inscriptions in runes . For most of the period, they followed the Old Norse religion , but later became Christians . The Vikings had their own laws , art , and architecture. Most Vikings were also farmers, fishermen, craftsmen, and traders. Popular conceptions of
9125-720: The Viking period are found in Sweden. Many runestones in Scandinavia record the names of participants in Viking expeditions, such as the Kjula runestone that tells of extensive warfare in Western Europe and the Turinge Runestone , which tells of a war band in Eastern Europe. Other runestones mention men who died on Viking expeditions. Among them are the England runestones (Swedish: Englandsstenarna ), which
9250-452: The Vikings and the Viking Age can also be important for understanding them and their culture, although they need to be treated cautiously. After the consolidation of the church and the assimilation of Scandinavia and its colonies into mainstream medieval Christian culture in the 11th and 12th centuries, native written sources began to appear in Latin and Old Norse. In the Viking colony of Iceland, extraordinary vernacular literature blossomed in
9375-701: The Vikings are contemporary texts from Scandinavia and regions where the Vikings were active. Writing in Latin letters was introduced to Scandinavia with Christianity, so there are few native documentary sources from Scandinavia before the late 11th and early 12th centuries. The Scandinavians did write inscriptions in runes , but these were usually very short and formulaic. Most contemporary documentary sources consist of texts written in Christian and Islamic communities outside Scandinavia, often by authors who had been negatively affected by Viking activity. Later writings on
9500-499: The Vikings come from other cultures that were in contact with them. Since the mid-20th century, archaeological findings have built a more complete and balanced picture of the lives of the Vikings. The archaeological record is particularly rich and varied, providing knowledge of their rural and urban settlement, crafts and production, ships and military equipment, trading networks, as well as their pagan and Christian religious artefacts and practices. The most important primary sources on
9625-523: The Vikings continued to have an influence in northern Europe. Likewise, King Harold Godwinson , the last Anglo-Saxon king of England, had Danish ancestors. Two Vikings even ascended to the throne of England, with Sweyn Forkbeard claiming the English throne in 1013 until 1014 and his son Cnut the Great being king of England between 1016 and 1035. Geographically, the Viking Age covered Scandinavian lands (modern Denmark , Norway and Sweden), as well as territories under North Germanic dominance, mainly
9750-506: The Vikings often strongly differ from the complex, advanced civilisation of the Norsemen that emerges from archaeology and historical sources. A romanticised picture of Vikings as noble savages began to emerge in the 18th century; this developed and became widely propagated during the 19th-century Viking revival . Perceived views of the Vikings as violent, piratical heathens or as intrepid adventurers owe much to conflicting varieties of
9875-640: The Waterside Bridge (crossing of the A975 road ) and the mouth of the Tarty Burn, a small tributary river. Based upon the habitat of the moorland bordering the east of the Ythan River near the mouth, this estuary is the most significant coastal moorland in the northern United Kingdom . The Ythan Estuary is a designated Site of Special Scientific Interest (SSSI) and appears as site no. 939 on
10000-630: The Worm), Meols (from merl meaning Sand Dunes), Snaefell (Snow Fell), Ravenscar (Ravens Rock), Vinland (Land of Wine or Land of Winberry ), Kaupanger (Market Harbour), Tórshavn (Thor's Harbour), and the religious centre of Odense , meaning a place where Odin was worshipped. Viking influence is also evident in concepts like the present-day parliamentary body of the Tynwald on the Isle of Man. Many common words in everyday English language stem from
10125-629: The Ythan Estuary. Studies date the lithics recovered at least as early as 7000 BC, with most of the artefacts from the Ythan mouth area deriving from the Sands of Forvie. Most of the large collection of lithics was retrieved in the period 1994-2001 from a deflation surface within this active dune system. The excavations revealed the survival of superimposed land surfaces, whose layers revealed hearth structures and other characteristic mesolithic artefacts. Although no Viking artefacts have been recovered here,
10250-523: The Ythan near the coast is a generally mild sloping farmland known as the Buchan plain, which is virtually devoid of trees. In the glacial era, the Ythan River at this point would have been a torrent of melt waters streaming down from the Scottish Highlands . Prehistoric man had settlements in coastal estuaries along the northeast Scottish coast including the nearby River Don Estuary and
10375-717: The absorption of Old Saxony into the Carolingian Empire . Fear of the Franks led the Vikings to further expand Danevirke, and the defence constructions remained in use throughout the Viking Age and even up until 1864. The southern coast of the Baltic Sea was ruled by the Obotrites , a federation of Slavic tribes loyal to the Carolingians and later the Frankish empire . The Vikings—led by King Gudfred —destroyed
10500-429: The actual time and height of the tide is affected by wind and atmospheric pressure . Many shorelines experience semi-diurnal tides—two nearly equal high and low tides each day. Other locations have a diurnal tide—one high and low tide each day. A "mixed tide"—two uneven magnitude tides a day—is a third regular category. Tides vary on timescales ranging from hours to years due to a number of factors, which determine
10625-423: The amphidromic point, the high tide passes New York Harbor approximately an hour ahead of Norfolk Harbor. South of Cape Hatteras the tidal forces are more complex, and cannot be predicted reliably based on the North Atlantic cotidal lines. Investigation into tidal physics was important in the early development of celestial mechanics , with the existence of two daily tides being explained by the Moon's gravity. Later
10750-429: The amphidromic point. For a semi-diurnal tide the amphidromic point can be thought of roughly like the center of a clock face, with the hour hand pointing in the direction of the high water cotidal line, which is directly opposite the low water cotidal line. High water rotates about the amphidromic point once every 12 hours in the direction of rising cotidal lines, and away from ebbing cotidal lines. This rotation, caused by
10875-547: The atmosphere which did not include rotation. In 1770 James Cook 's barque HMS Endeavour grounded on the Great Barrier Reef . Attempts were made to refloat her on the following tide which failed, but the tide after that lifted her clear with ease. Whilst she was being repaired in the mouth of the Endeavour River Cook observed the tides over a period of seven weeks. At neap tides both tides in
11000-636: The centre of the Islamic Empire . The Norse regularly plied the Volga with their trade goods: furs, tusks, seal fat for boat sealant, and slaves . Important trading ports during the period include Birka , Hedeby , Kaupang , Jorvik , Staraya Ladoga , Novgorod , and Kiev. Scandinavian Norsemen explored Europe by its seas and rivers for trade, raids, colonisation, and conquest. In this period, voyaging from their homelands in Denmark, Norway and Sweden
11125-410: The coast. Semi-diurnal and long phase constituents are measured from high water, diurnal from maximum flood tide. This and the discussion that follows is precisely true only for a single tidal constituent. For an ocean in the shape of a circular basin enclosed by a coastline, the cotidal lines point radially inward and must eventually meet at a common point, the amphidromic point . The amphidromic point
11250-526: The countries they raided and settled in, this period is popularly known as the Viking Age , and the term "Viking" also commonly includes the inhabitants of the Scandinavian homelands as a whole. The Vikings had a profound impact on the early medieval history of Scandinavia , the British Isles , France , Estonia , and Kievan Rus' . Expert sailors and navigators of their characteristic longships , Vikings established Norse settlements and governments in
11375-480: The daily tides were explained more precisely by the interaction of the Moon's and the Sun's gravity. Seleucus of Seleucia theorized around 150 BC that tides were caused by the Moon. The influence of the Moon on bodies of water was also mentioned in Ptolemy 's Tetrabiblos . In De temporum ratione ( The Reckoning of Time ) of 725 Bede linked semidurnal tides and the phenomenon of varying tidal heights to
11500-487: The early 21st century derives Viking from the same root as Old Norse vika 'sea mile', originally referring to the distance between two shifts of rowers, ultimately from the Proto-Germanic * wîkan 'to recede'. This is found in the early Nordic verb *wikan 'to turn', similar to Old Icelandic víkja 'to move, to turn', with "well-attested nautical usages", according to Bernard Mees. This theory
11625-571: The end of the Viking Age for the Scandinavians also marks the start of their relatively brief Middle Ages. Slavic and Viking tribes were "closely linked, fighting one another, intermixing and trading". In the Middle Ages, goods were transferred from Slavic areas to Scandinavia, and Denmark could be considered "a melting pot of Slavic and Scandinavian elements". Leszek Gardeła, of the Department of Scandinavian Languages and Literatures at
11750-423: The estuary, there are mussel beds and marshy areas. At its widest point the Ythan Estuary is approximately 780 metres (2,560 ft) wide. The verges of the upper reaches range from extensive mudflats to marsh and fen. Further upstream is a small island known as Geck Island ( grid reference NJ999278 ) inaccessible to waders even at low tide, and which is a haven for cormorants. The broader landscape drained by
11875-493: The first to be documented by eyewitnesses, and they were much larger in scale and frequency than in previous times. Vikings themselves were expanding; although their motives are unclear, historians believe that scarce resources or a lack of mating opportunities were a factor. The slave trade was an important part of the Viking economy, with most slaves destined to Scandinavia although many others were shipped east where they could be sold for large profits. The "Highway of Slaves"
12000-538: The first to map co-tidal lines, for Great Britain, Ireland and adjacent coasts, in 1840. William Whewell expanded this work ending with a nearly global chart in 1836. In order to make these maps consistent, he hypothesized the existence of a region with no tidal rise or fall where co-tidal lines meet in the mid-ocean. The existence of such an amphidromic point , as they are now known, was confirmed in 1840 by Captain William Hewett, RN , from careful soundings in
12125-453: The former Polish queen of Sweden, wife of Eric. Colonisation of Iceland by Norwegian Vikings began in the 9th century. The first source mentioning Iceland and Greenland is a papal letter from 1053. Twenty years later, they appear in the Gesta of Adam of Bremen . It was not until after 1130, when the islands had become Christianised, that accounts of the history of the islands were written from
12250-420: The highest level to the lowest: The semi-diurnal range (the difference in height between high and low waters over about half a day) varies in a two-week cycle. Approximately twice a month, around new moon and full moon when the Sun, Moon, and Earth form a line (a configuration known as a syzygy ), the tidal force due to the Sun reinforces that due to the Moon. The tide's range is then at its maximum; this
12375-415: The idea that the attraction of the Moon was responsible for the tides and spoke in clear terms about ebb, flood, spring tide and neap tide , stressing that further research needed to be made. In 1609 Johannes Kepler also correctly suggested that the gravitation of the Moon caused the tides, which he based upon ancient observations and correlations. Galileo Galilei in his 1632 Dialogue Concerning
12500-478: The influx of Islamic silver from the East had been absent for more than a century, and the flow of English silver had come to an end in the mid-11th century. Christianity had taken root in Denmark and Norway with the establishment of dioceses in the 11th century, and the new religion was beginning to organise and assert itself more effectively in Sweden. Foreign churchmen and native elites were energetic in furthering
12625-468: The interaction was mediated by the pneuma . He noted that tides varied in time and strength in different parts of the world. According to Strabo (1.1.9), Seleucus was the first to link tides to the lunar attraction, and that the height of the tides depends on the moon's position relative to the Sun. The Naturalis Historia of Pliny the Elder collates many tidal observations, e.g., the spring tides are
12750-513: The interests of Christianity, which was now no longer operating only on a missionary footing, and old ideologies and lifestyles were transforming. By 1103, the first archbishopric was founded in Scandinavia, at Lund , Scania, then part of Denmark. The assimilation of the nascent Scandinavian kingdoms into the cultural mainstream of European Christendom altered the aspirations of Scandinavian rulers and of Scandinavians able to travel overseas, and changed their relations with their neighbours. One of
12875-477: The kings of Denmark and Sweden participated actively in the Baltic Crusades of the 12th and 13th centuries. A variety of sources illuminate the culture, activities, and beliefs of the Vikings. Although they were generally a non-literate culture that produced no literary legacy, they had an alphabet and described themselves and their world on runestones . Most contemporary literary and written sources on
13000-543: The late 11th century, royal dynasties were legitimised by the Catholic Church (which had had little influence in Scandinavia 300 years earlier) which were asserting their power with increasing authority and ambition, with the three kingdoms of Denmark, Norway, and Sweden taking shape. Towns appeared that functioned as secular and ecclesiastical administrative centres and market sites, and monetary economies began to emerge based on English and German models. By this time
13125-416: The modern Viking myth that had taken shape by the early 20th century. Current popular representations of the Vikings are typically based on cultural clichés and stereotypes, complicating modern appreciation of the Viking legacy. These representations are rarely accurate—for example, there is no evidence that they wore horned helmets , a costume element that first appeared in the 19th century. The etymology of
13250-412: The month is divided into four parts of seven or eight days with alternating malinae and ledones . In the same passage he also notes the effect of winds to hold back tides. Bede also records that the time of tides varies from place to place. To the north of Bede's location ( Monkwearmouth ) the tides are earlier, to the south later. He explains that the tide "deserts these shores in order to be able all
13375-514: The more to be able to flood other [shores] when it arrives there" noting that "the Moon which signals the rise of tide here, signals its retreat in other regions far from this quarter of the heavens". Later medieval understanding of the tides was primarily based on works of Muslim astronomers , which became available through Latin translation starting from the 12th century. Abu Ma'shar al-Balkhi (d. circa 886), in his Introductorium in astronomiam , taught that ebb and flood tides were caused by
13500-420: The obliquity (tilt) of the Earth's Equator and rotational axis, the inclination of the plane of the lunar orbit and the elliptical shape of the Earth's orbit of the Sun. A compound tide (or overtide) results from the shallow-water interaction of its two parent waves. Because the M 2 tidal constituent dominates in most locations, the stage or phase of a tide, denoted by the time in hours after high water,
13625-426: The oceans, but can occur in other systems whenever a gravitational field that varies in time and space is present. For example, the shape of the solid part of the Earth is affected slightly by Earth tide , though this is not as easily seen as the water tidal movements. Four stages in the tidal cycle are named: Oscillating currents produced by tides are known as tidal streams or tidal currents . The moment that
13750-568: The place names in Normandy like Tocqueville (Toki's farm). Linguistic and etymological studies continue to provide a vital source of information on the Viking culture, their social structure and history and how they interacted with the people and cultures they met, traded, attacked or lived with in overseas settlements. A lot of Old Norse connections are evident in the modern-day languages of Swedish , Norwegian , Danish , Faroese and Icelandic . Old Norse did not exert any great influence on
13875-514: The point of view of the inhabitants in sagas and chronicles. The Vikings explored the northern islands and coasts of the North Atlantic, ventured south to North Africa, east to Kievan Rus (now – Ukraine, Belarus), Constantinople , and the Middle East. They raided and pillaged, traded, acted as mercenaries and settled colonies over a wide area. Early Vikings probably returned home after their raids. Later in their history, they began to settle in other lands. Vikings under Leif Erikson , heir to Erik
14000-491: The present day nations of Norway, Sweden and Denmark did not exist, but the peoples who lived in what is now those countries were largely homogeneous and similar in culture and language, although somewhat distinct geographically. The names of Scandinavian kings are reliably known for only the later part of the Viking Age. After the end of the Viking Age, the separate kingdoms gradually acquired distinct identities as nations, which went hand-in-hand with their Christianisation . Thus,
14125-427: The primary sources of profit for the Vikings had been slave-taking from other European peoples. The medieval Church held that Christians should not own fellow Christians as slaves, so chattel slavery diminished as a practice throughout northern Europe. This took much of the economic incentive out of raiding, though sporadic slaving activity continued into the 11th century. Scandinavian predation in Christian lands around
14250-408: The problem from the perspective of a static system (equilibrium theory), that provided an approximation that described the tides that would occur in a non-inertial ocean evenly covering the whole Earth. The tide-generating force (or its corresponding potential ) is still relevant to tidal theory, but as an intermediate quantity (forcing function) rather than as a final result; theory must also consider
14375-471: The river mouth species of birds include scaup , long-tailed duck , red-breasted merganser and velvet scoter . In lesser numbers guillemot and razorbills are occasionally seen at this outlet to the North Sea. Extensive mussel beds are found about three kilometres from the estuary mouth, and these provide food for common eider (with the occasional king eider , oystercatchers and turnstones ). On
14500-493: The sea or to navigable rivers. Lack of organised naval opposition throughout Western Europe allowed Viking ships to travel freely, raiding or trading as opportunity permitted. The decline in the profitability of old trade routes could also have played a role. Trade between Western Europe and the rest of Eurasia suffered a severe blow when the Western Roman Empire fell in the 5th century. The expansion of Islam in
14625-448: The sense of the contour level of a particular low pressure in the outer atmosphere. In most locations, the largest constituent is the principal lunar semi-diurnal , also known as the M2 tidal constituent or M 2 tidal constituent . Its period is about 12 hours and 25.2 minutes, exactly half a tidal lunar day , which is the average time separating one lunar zenith from the next, and thus
14750-696: The service of the Byzantine Empire . In the late 10th century, a new unit of the imperial bodyguard formed. Traditionally containing large numbers of Scandinavians, it was known as the Varangian Guard. The word Varangian may have originated in Old Norse, but in Slavic and Greek it could refer either to Scandinavians or Franks. In these years, Swedish men left to enlist in the Byzantine Varangian Guard in such numbers that
14875-597: The term "Viking" may have evolved to become "a job description, not a matter of heredity", at least in some Viking bands. The motives driving the Viking expansion are a topic of much debate. The concept that Vikings may have originally started sailing and raiding due to a need to seek out women from foreign lands was expressed in the 11th century by historian Dudo of Saint-Quentin in his semi-imaginary History of The Normans . As observed by Adam of Bremen, rich and powerful Viking men tended to have many wives and concubines; and these polygynous relationships may have led to
15000-443: The tidal current ceases is called slack water or slack tide . The tide then reverses direction and is said to be turning. Slack water usually occurs near high water and low water, but there are locations where the moments of slack tide differ significantly from those of high and low water. Tides are commonly semi-diurnal (two high waters and two low waters each day), or diurnal (one tidal cycle per day). The two high waters on
15125-494: The tides. Isaac Newton (1642–1727) was the first person to explain tides as the product of the gravitational attraction of astronomical masses. His explanation of the tides (and many other phenomena) was published in the Principia (1687) and used his theory of universal gravitation to explain the lunar and solar attractions as the origin of the tide-generating forces. Newton and others before Pierre-Simon Laplace worked
15250-532: The word Viking has been much debated by academics, with many origin theories being proposed. One theory suggests that the word's origin is from the Old English wicing 'settlement' and the Old Frisian wizing , attested almost 300 years prior. Another less popular theory is that víking came from the feminine vík 'creek', 'inlet', 'small bay'. Another etymology that gained support in
15375-480: The work " Histoire de la mission de pères capucins en l'Isle de Maragnan et terres circonvoisines ", where he exposed that the Tupinambá people already had an understanding of the relation between the Moon and the tides before Europe. William Thomson (Lord Kelvin) led the first systematic harmonic analysis of tidal records starting in 1867. The main result was the building of a tide-predicting machine using
15500-509: Was a term for a route that the Vikings found to have a direct pathway from Scandinavia to Constantinople and Baghdad while traveling on the Baltic Sea. With the advancements of their ships during the 9th century, the Vikings were able to sail to Kievan Rus and some northern parts of Europe. Jomsborg was a semi-legendary Viking stronghold at the southern coast of the Baltic Sea (medieval Wendland , modern Pomerania ), that existed between
15625-522: Was established around 980, during the Medieval Warm Period , and its demise by the mid-15th century may have been partly due to climate change . The Viking Rurik dynasty took control of territories in Slavic and Finnic -dominated areas of Eastern Europe; they annexed Kiev in 882 to serve as the capital of the Kievan Rus' . As early as 839, when Swedish emissaries are first known to have visited Byzantium , Scandinavians served as mercenaries in
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