The North Sea Empire, also known as the Anglo-Scandinavian Empire, was the personal union of the kingdoms of England, Denmark and Norway for most of the period between 1013 and 1042 towards the end of the Viking Age. This ephemeral Norse-ruled empire was a thalassocracy,Blomkvist, N., 2016. Europe’s Captive. Medieval Baltic Torn between Thalassocratic and Continental Principles of Exploitation. Vorträge und Forschungen, 83, pp. 213-232.Heebøll-Holm, T.K., 2019. Medieval Denmark as a Maritime Empire. Empires of the Sea, pp. 194-218. its components only connected by and dependent upon the sea.
The first king to unite all three kingdoms was Sweyn Forkbeard, king of Denmark since 986 and of Norway since 1000, when he conquered England in 1013. He died in the following year, and his realm was divided. His son Cnut the Great acquired England in 1016, Denmark in 1018 and Norway in 1028. He died in 1035 and his realm was again divided, but his successor in Denmark, Harthacnut, inherited England in 1040 and ruled it until his death in 1042. At the height of his power, when Cnut ruled all three kingdoms (1028–1035), he was the most powerful ruler in western Europe after the Holy Roman Emperor.
Etymology The term "North Sea Empire" was coined by historians at the beginning of the 20th century, although the conception of Cnut's domains as having constituted an empire can be found as early as 1623, in John Speed's Histoire of Great Britaine. Historically, the union was referred to by its individual parts: the kingdoms of Denmark, Norway, and England. As a largely maritime empire, it is often considered a thalassocracy.
Formation England
Cnut was the younger son of the Danish king Sweyn Forkbeard.
In early 1014 Sweyn and the Danes were in the midst of invading England. Cnut joined the expedition, and was given command of the fleet in the River Trent during one of Sweyn's visit to the south.
Sweyn died on 3 February, and Cnut had the early support of his Danish troops. But the invasion fell apart as the men of the Kingdom of Lindsey failed to supply horses they had promised. English nobles then reinstalled King Æthelred—whom they had previously deposed and exiled—after he promised reforms, and Cnut returned to Denmark.
Cnut's brother Harald succeeded Sweyn as King of Denmark. With the Danish throne out of his grasp, Cnut decided to invade England in his own right. He raised a fleet by promising shares of spoils and embarked for England in the summer of 1015; Eric Haakonsson of Norway provided. The English were divided by intrigue among Æthelred the king, his sons, and other nobles, and the moment was opportune for Cnut to invade.
Æthelred died on 23 April 1016—before Cnut could begin his attack in earnest—and a succession crisis ensued. Londoners chose Æthelred's son Edmund as his replacement, but the nobility swore fealty to Cnut at Southampton. Cnut began his campaign with a blockade of London, but was beaten by Edmund at the Battle of Otford. The Danes then moved into Essex where they defeated Edmund's forces at the Battle of Assandun. Edmund and Cnut struck an agreement under which Edmund would retain Wessex and Cnut would rule all of England north of the River Thames. Edmund's rule was to be short; he died on 30 November 1016, which left Cnut as the sole King of England.
Cnut cemented his power by marrying Æthelred's widow Emma in the summer of 1017. (He was already married to another English noblewoman, Ælfgifu of Northampton, at this time). In 1018, he paid off his invasion fleet—with money contributed largely from the citizens of London—and was fully recognised as King of England.
Denmark
King Harald died childless in 1018 or 1019, leaving the country without a king. Cnut was his brother's heir and went to Denmark in 1019 to claim the throne. While in Denmark he sent his subjects in England a letter saying he was abroad to avert an unspecified "danger", and he only returned to quell incipient rebellions. One Danish chronicle states that the Danes had previously deposed Harald in favour of Cnut, then brought back Harald because of Cnut's frequent absences.
King Olaf II of Norway and King Anund Jacob of Sweden viewed the combined Anglo-Danish kingdom as a threat—Cnut's father Sweyn had asserted power over both their countries. Olaf attacked Denmark in 1025 or 1026 during one of Cnut's frequent absences. Ulf Jarl, Cnut's brother-in-law and former Danish regent, and Ulf's brother, joined the battle. Cnut surprised Olaf and defeated the Swedish fleet at the Battle of the Helgeå. Olaf fled, thus abandoning his designs on Cnut's rule in Denmark.; . Ulf's assistance at Helgeå did not allay Cnut's suspicions of Ulf's treachery. Chronicles say that on Christmas of 1026, Cnut ordered a housecarl to murder Ulf in , later Roskilde Cathedral, on the Danish island of Zealand.Separate Saga of St. Olaf, chapter 144.
Cnut went to Rome in 1027; the visit would have been both personal—penance for his sin of ordering Ulf's murder—and political—to assert himself as an equal to any other European monarch at the coronation of Conrad II as Holy Roman Emperor. The visit was fruitful. Cnut negotiated a reduction on tolls levied on Northern European pilgrims to Rome, and on the Papal tax on the pallium granted to English archbishops. He persuaded the Emperor to cede back to Denmark Schleswig and a strip of ancient Danish territory between Hedeby and the Eider that the Germans had been occupying. And the Emperor agreed to have his son Henry marry Cnut's daughter Gunnhild, further strengthening ties.;
Norway
Olaf II had extended his power throughout Norway while Jarl Erik was with Cnut in England. Cnut's enmity with him extended further back: Æthelred had returned to England in a fleet provided by Olaf.Herbert A. Grueber and Charles Francis Keary, A Catalogue of English Coins in the British Museum: Anglo-Saxon Series, Volume 2, London: Trustees [of the British Museum], 1893, p. lxxvii . In 1024, Cnut had offered to let Olaf govern Norway as his vassal;. but after Helgeå, he set about undermining his unpopular rule with bribes, and in 1028 set out with 50 ships to subjugate Norway. A large contingent of Danish ships joined him, and Olaf withdrew into the Oslo Fjord while Cnut sailed along the coast, landing at various points and receiving oaths of allegiance from the local chieftains. Finally at Nidaros, now Trondheim, he was acclaimed king at the Eyrathing, and in a few months Olaf fled to Sweden.; Karen Larsen, A History of Norway, The American-Scandinavian Foundation, Princeton, NJ: Princeton University, 1948, repr. 1950, , p. 104
In 1030, Olaf attempted to return, but the people of the Trondheim area did not want him back and he was defeated and killed at the Battle of Stiklestad.
Sweden
After Helgeå, Cnut also claimed to rule "part of Sweden" together with England, Denmark, and Norway.In the probably later heading to a 1027 letter sent to his English subjects: Rex totius Angliæ et Denemarciæ et Norreganorum et partis Suanorum, "King of all England and Denmark and Norway and part of Sweden". Freeman, p. 479, note 2 . There is evidence for his having had coins minted either in the capital Sigtuna or in Lund—then part of Denmark—with the inscription CNVT REX SW ("Cnut King of the Swedes"). (Western Geatland or Blekinge have also been suggested as production locales).Brita Malmer, "The 1954 Rone Hoard and Some Comments on Styles and Inscriptions of Certain Scandinavian Coins from the Early Eleventh Century", in Coinage and History in the North Sea World, c. AD 500–1200: Essays in Honour of Marion Archibald, ed. Barrie Cook and Gareth Williams, Leiden: Brill, 2006, , pp. 435–48, p. 443 . The inscription may have been propaganda or boasting, as Cnut did not actually have to be present in Sweden for these coins to be produced—he also had coins minted which proclaimed him ruler of Ireland.Henry Noel Humphreys, The Coinage of the British Empire: An Outline of the Progress of the Coinage in Great Britain and her Dependencies, From the Earliest Period to the Present Time, London: Bogue, 1855, , p. 54 ; "The Hiberno–Norse Coinage of Ireland, ~995 to ~1150" These coins are however usually regarded as copies of coins minted in Denmark (curiously, coins stating that the Swedish king Olof Skötkonung was King of England have also been found in Sigtuna).Hagerman, M., 'Spåren av kungens män', 1996, p=135Sawyer, P. När Sverige blev Sverige (Occasional papers on medieval topics, 1991, p=23 Irish coinage and Swedish history at this early date is very uncertain.Franklin D. Scott, Sweden: The Nation's History, 2nd ed. Carbondale: Southern Illinois University, 1988, , pp. 25–26 , listing Cnut's claim.
Ouster
Anglo-Saxon sources state Anund Jakob won the Battle of Helgeå.The Anglo-Saxon Chronicle (Part 4: A.D. 1015 – 1051), at the Medieval and Classical Literature Library The Danes controlled Svealand for at most three years. Anund ousted Cnut; Swedish sources assert that Anund controlled the country by 1030, and the 11th-century chronicler Adam of Bremen described Anund choosing the bishops for all of Sweden. In that same year, Olaf attempted to retake the Norwegian throne from Cnut, his second such attempt; Anund supported Olaf and sent Swedish troops to aid his campaign.Adam av Bremen (1984), p. 104 (Book II, Chapter 61)
Tributary areas Cnut allied with the Poles and received tribute from the Wends. In 1022, together with Godwin and Ulf Jarl, he took a fleet east into the Baltic to consolidate his rule over the coastal areas which the Danish kings had dominated from Jomsborg.
Upon returning to Britain from his 1027 visit to Rome, Cnut led an army into Scotland and made vassals of three of its kings; one of these was High King Malcolm. Another was Echmarcach mac Ragnaill, a sea-king whose lands included Galloway and the Isle of Man and who would become king of Dublin in 1036. It is likely that the WelshM.K. Lawson, Cnut: England's Viking King, Stroud: Tempus, 2004, , p. 103: "Cnut's power would seem in some sense to have extended into Wales". paid Cnut tribute on the model of the Danegeld that Æthelred had instituted to pay off the Danes. Cnut's rule re-inaugurated Anglo-Danish dominion over the Celtic kingdoms that had weakened under English kings; he punished those who had supported Olaf against him. A verse by the Icelandic skald Óttarr svarti calls Cnut "king of the Danes, the Irish, the English and the Islanders"; Norway is not named as Cnut had not yet come to power there.Benjamin T. Hudson, Viking Pirates and Christian Princes: Dynasty, Religion, and Empire in the North Atlantic, New York: Oxford University, 2005, , p. 119 .
Religion
By the early 11th century, England had been Christian for centuries; the Danelaw was in transition from paganism to Christianity,Lauring, p. 56: "the Danes in England very quickly became Christians". but the Scandinavian countries were still predominantly pagan.Starcke, p. 283. Cnut's father, Sweyn, had initially been pagan but in later life had been basically Christian.Stenton, pp. 396–397: "Swein ... first appears in history as the leader of a heathen reaction ... [but] behaved as at least a nominal Christian in later life. ... Swein's tepid patronage of Christianity ..." In England, Cnut assiduously promoted the interests of the Church, and this brought him acceptance from the Christian rulers of Europe that no other Scandinavian king had previously been accorded.Stenton, p. 397: "the first viking leader to be admitted into the civilised fraternity of Christian kings". In Norway, in contrast, he built churches and was both respectful and generous to the clergy, but also made allies of the heathen chieftains, and unlike Olaf, did not make laws benefitting the Church until his power was on a solid footing.
Governance