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Sweyn Forkbeard

NameSweyn I, Svein, Svend Tveskaeg (960s – 1014).
King of Denmark (986–1014). King of Norway (986-995, 1000-1014). King of England (1013-1014).
FamilyHouse of Gorm.
Parents are Harald Bluetooth and Gunhild or Tove.
Married to (1) Gunhild (?) (2) Sigrid the Haughty (?).
Children: Harald II, Cnut the Great, Estrid, Gytha, Gunnhild, Santslaue, Thyra.
Life980s – Defeats his father in battle and is crowned king of Denmark.
1000 – Battle of Svold where he defeats Olaf Tryggvason.
1003-1004 – First invasion of England.
1006-1007 – Second invasion of England.
1009 – Sends Thorkell the Tall to invade England.
1013 – Third invasion of England.
Sources: BBC, Britannica, PASE, Danmarks Historien.
Sweyn Forkbeard (Source: Wikipedia).

Sweyn I Haraldsson is better known as Sweyn Forkbeard, or Svend Tveskaeg. He is born in the 960s CE, but the exact date of birth is unknown. As a Danish prince, he leads an eventful life and becomes one of the most powerful European kings of his time. His children will continue his legacy. His sons will be kings of the Danes and his daughters will continue the royal lineages in Denmark and England.1

The Evidence

No more than a rune stone and a coin refer to Sweyn Forkbeard. It is all the archaeological evidence for this Danish king.2 In contrast, there is a wealth of mediaeval sources. Chronicles, sagas, and charters. Some are Anglo-Saxon, some German, others Scandinavian. At best, their contents contradict each other. At worst, they are downright biased and full of errors.3

It is hard to discern the truth about Forkbeard’s life when all sources except one put him in a bad light. The oldest are written by German clergymen in the service of the Archbishops of Hamburg-Bremen. This diocese dictates the Church in early medieval Scandinavia, but its influence is waning by the late tenth century. Sweyn moves assertively to take control of the Church in Denmark. This does not go well with the Germans, so in response, Thietmar of Merseburg and Adam of Bremen go to great pains to depict him as a pagan, brutal king.4

Encomium Emmae Reginae BL.MS.Add.33241 (Source: Wikipedia).

More negativity is offered by the Anglo-Saxon sources. This comes as no surprise since Sweyn spends much time raiding and invading England. And yet, even the Scandinavian sources do not take kindly to him. His fellow countrymen copy Adam and Thietmar’s works including the harsh tone. Other texts are mainly written by Norwegians and Icelanders offering their own view on Danish affairs. In the case of the sagas, this view is particularly literary, such as the Jómsvíkinga Saga (JS).5

The only source discussing Sweyn positively is the Encomium Emmae Reginae (Encomium). This, too, is biased as the patron is none other than Emma of Normandy, wife to Sweyn’s son Cnut and mother of Sweyn’s grandsons.6

A Reconstruction

Parentage and Youth

Sweyn’s birth and youth are a mystery. His mother may have been anyone from a queen to a lowly servant. Yet, the sources generally agree that his father is Harald I ‘Bluetooth’.7 Most texts also suggest that when Sweyn finally comes of age, Harald is in no hurry to install him as his successor to the Danish throne.

What the sources also say Even the Encomium scribe remains silent on Sweyn’s youth. The JS is the only source to elaborate on this period. In the saga, Sweyn is born from an encounter of Harald with a lowly woman on the Danish island of Fyn. After Harald refuses to acknowledge him, a local chieftain takes Sweyn in as his foster son. This chieftain is none other than Pálna-Tóki, the founder of the Jomsvikings.8 This storyline is a literary technique to establish a strong connection between Sweyn and the Jomsvikings. The saga scribe implies Harald’s refusal to acknowledge Sweyn as an act of jealousy.

Early Reign

Viking and Slavic Festival in Volin (Source: Flickr / Jakub Jankiewicz).

Whatever Harald’s reason for the delay in naming his successor, Sweyn takes matters in to his own hands. He confronts his father on the battlefield by the late 980s. Harald eventually flees and dies shortly afterwards. Meanwhile, the Danish nobles accept Sweyn as their next king. Little is known about events in the following years. All seems quiet. Norway is under control of Jarl Haakon, Sweyn’s puppet ruler. The Swedes and Wends are busy forming an alliance through marriage. And down south, the new Holy Roman Emperor is a mere child of four years old.9

What the sources also say What are the chances that things are really quiet? Sweyn inherits a Christian kingdom with a strong military infrastructure, giving him a strong base to operate from.10 

He starts by diminishing the influence of the German Archdiocese. The bishops flee, most likely to Germany where Otto III confirms their rights in a charter in 988. Only one bishop remains in Denmark, an Anglo-Saxon named Gudewald.11 However, Sweyn does not seem as pagan as Adam would have us believe as during his reign churches such as those in Lund and Roskilde are built.12 According to the JS and Thietmar, Sweyn is also occupied by political intrigues with the Jomsvikings during this time. He is abducted for ransom and forced to marriage a Polish princess.13 The last and most persistent storyline, is that of Sweyn’s exile. Adam states that Erik I of Sweden invades Denmark and sends Sweyn to exile in Scotland.14 To this day, modern scholars are still debating whether this really happened.15


Exiled or not, the Anglo-Saxon sources confirm Sweyn ends up in England at one point. One text is a charter, the will of Aethelric of Bocking. They suspect him of aiding Sweyn when he arrives with a fleet in Essex. The charter is undated but according to the historian Peter Sawyer the wording makes it clear this event could only have happened before 994.16 Whether or not Sweyn sails for England before 994, he is definitely sighted in 994. The ASC confirms his name in the attack on London alongside Olaf Tryggvason.17 Another document is the peace treaty II Aethelred, signed by the Anglo-Saxons and Viking raiders. Olaf Tryggvason’s name is on the document, but Sweyn’s is not.18 This is strange, as a large amount of Danegeld is involved and it seems Sweyn would not turn his share down. But he does.

What the sources also say In the Heimskringla, Snorri Sturluson states that Erik I ‘the Victorious’, the man who exiled Sweyn, dies in 994. Not all scholars believe this due to little confirmation elsewhere. On the other hand, if this is true it would explain why Sweyn ignores the Danegeld and returns to reclaim his kingdom.19

And Enemies

Around 994, the Scandinavian sources pick up Sweyn’s story again. It is fair to assume Sweyn returns to Denmark and then spends most of his time here until 1000 whilst the northern political landscape is changing.

Olaf Tryggvason, his former ally in England, claims the Norwegian crown in 995 and kills Sweyn’s puppet ruler.20 In a struggle for strong alliances, Olaf loses out on a marriage to Erik I’s widow. Sweyn marries her instead and becomes the stepfather of the Swedish king Olof Skötkonung.21 The final showdown between Sweyn and Olaf takes place at the battle of the Svold in 1000. Olaf is ambushed and disappears in battle. Sweyn takes back his former territories in Norway and instals the son of Jarl Haakon, Erik, as his new puppet ruler.22 At the turn of the millennium, Sweyn Forkbeard rules Scandinavia in all but name.

Sweyn Forkbeard coin (Source: Wikipedia).

The connection with England remains, though. The aforementioned bishop is not a unique sign. Upon his return to Denmark, Sweyn also introduces the first Danish coins modeled after the Anglo-Saxon Crux model of Aethelred II and minted in Lund by a mint master called Godwine.23

What the sources also say The sources do not describe Sweyn’s reaction to Olaf taking the Norwegian crown, but he cannot have been happy losing his domains there. Olaf swiftly moves forward, boldly trying to make a pact with Sweden by offering marriage to Erik I’s widow. She famously snubs him for his religious zeal and marries Sweyn instead. After that, Sweyn offers his sister Thyra in marriage to the Wendish king. But instead, she elopes with Olaf who pays for this deceit with his life.24

Land of Invasions

With Scandinavia and the Baltic firmly under his control, Sweyn seems uninterested expanding his kingdom southwards. Even if the German Holy Roman Empire is at its weakest after the death of Otto III and no heir apparent.25 Instead, his name is mentioned again in the Anglo-Saxon sources. The ASC reports his fleet sailing for East Anglia in 1003–1004. Aided by Anglo-Saxon noblemen, he makes significant advances until he is forced to retreat when famine hits.

He returns again in 1006–1007 and by 1009 he sends fellow Jomsviking, Thorkell the Tall.[26] Thorkell makes good headway, but defects to Aethelred II. Whether this a clever trick of Aethelred, or a Danish master plan remains a question. Yet, the sagas speak well of Thorkell in later years and Sweyn does not kill him for this plain treachery. Sweyn’s son Cnut even makes him Jarl in 1017.26

The Sweyn Forkbeard Pub in Gainsborough, Lincolnshire (Source: Flickr / Brian).

England’s fate is sealed in 1013. Sweyn invades once more, again with the support of local ealdormen.27 He sends Aethelred II into exile and now rules Denmark, Norway and England. His days are short-lived, though. As he settles down in his base in Gainsborough, he dies only forty days later.28

What the sources also say Why did Sweyn go to England in 1003? Did he need money to keep his Danish nobles satisfied? William of Malmesbury gives a very different motivation. The scribe writes how on St Brice’s Day massacre, Sweyn’s sister and her husband who lived in England are among the murdered. Thus, Sweyn sails for England in revenge.29

After his death he is first buried in York, but when Aethelred speaks of his intention to desecrate the grave, the remains are hastily taken to Denmark.30

A Legacy

How many wives Sweyn had during his lifetime, is unknown. Of his children, four are known from the sources: Gytha who marries Jarl Erik (Norway), Harald II who will be king of the Danes, Cnut I ‘the Great’ who will succeed his brother as king of the Danes, but also rule Norway and England, and Estrid who marries and divorces Duke Richard of Normandy. She then marries Jarl Ulf and their son Sven Estridsson will become the first in a long dynasty of Danish kings.31

What the sources also say Thietmar of Merseburg, the JS and the Encomium state that Sweyn marries a Wendish princess. And in particular that Sweyn’s sons go to Slavia to fetch their mother. Thietmar mentions she is the daughter of the Polish ruler Mieczko. The JS suggests, though, she might have been the daughter of Boleslaw, Mieczko’s son who succeeded him in 992.32

Learn More

Rex Factor Podcast – Episode 64. Sweyn Forkbeard.
Medieval Archives Podcast – Episode 48. Sweyn Forkbeard, Viking king of England.
The History of England Podcast – Episode 15. Aethelred, Svein Forkbeard, And Years of Misery.
The Vikings Podcast – Episode 211. Vikings Updates and Sven Forkbeard.


  1. The Editors of Encyclopædia Britannica, ‘Sweyn I | King of Denmark and England,’ Encyclopedia Britannica Online ↩
  2. Peter Sawyer, ‘Swein Forkbeard and the Historians.’ In: Church and Chronicle in the Middle Ages. Edited by Ian Wood and Graham Loud (London: The Hambledon Press, 1991), pp. 36 [pp. 27–40].
    Svein H. Gullbekk, ‘Coinage and monetary economies.’ In: The Viking World. Edited by Stefan Brink in collaboration with Neil Price (Abingdon: Routledge, 2012), pp. 162 [pp. 159–169].  ↩
  3. Read Sawyer’s article (1991) for a sharp analysis.  ↩
  4. For example, Ottonion Germany: The Chronicon of Thietmar of Merseburg. Translated and annotated by David A. Warner (Manchester: Manchester University Press, 2001), pp. 333.
    Niels Lund, ‘Harald Bluetooth – A Saint Very Nearly Made by Adam of Bremen.’ In: The Scandinavian from the Vendel Period until the Tenth Century: An Ethnographic Perspective, edited by Judith Jesch. (Woodbridge: Boydell Press, 2002), pp. 305–6.  ↩
  5. Anonymous, “The Anglo–Saxon Chronicle.” The Avalon Project | Documents in Law, History and Diplomacy. Accessed November 22, 2017, Yale University.
    Snorri Sturlason, Heimskringla or The Chronicle of the Kings of Norway. Edited by Douglas B. Killings and David Widger. The Project Gutenberg EBook of Heimskringla. Published 27 November 2009. Last Updated 6 February 2013. Last Accessed 11 September 2018. Project Gutenberg ↩
  6. Encomium Emmae Reginae Edited by Alastair Campbell (London: The Royal Historical Society, 1949), pp. liii, 9.  ↩
  7. Alison Finlay, ‘Jómsvíkinga Saga and Genre’, in: Scripta Islandica, Volume 65, pp. [pp. 63–79].
    Jómsvíkinga Saga | The Saga of the Jomsvikings. Translated by N.F. Blake (Edinburgh: Thomas Nelson and Sons Ltd, 1962), pp. xiv.  ↩
  8. The fullest account of Sweyn’s youth is described in the JS (1962), pp. 12.
    Niels Lund (2002), pp. 304.  ↩
  9. The Editors of Encyclopædia Britannica, ‘Otto III | Holy Roman Emperor,’ Encyclopedia Britannica Online. Last Accessed 02 August 2018.  ↩
  10. Helen Goodchild, Nanna Holm & Søren Sindbæk, ‘Borgring: The discovery of a Viking Age ring fortress’. In: Antiquity Volume 91.358 (2017), pp. 1040 [pp. 1027–1042].
    Niels Lund (2002), pp. 305–6.  ↩
  11. Sawyer (1991), pp. 32.
    Martin Schwarz Lausten, A Church History of Denmark. (Abingdon: Routledge, 2016), pp. 14.  ↩
  12. Sawyer (1991), pp. 39.  ↩
  13. JS (1962), pp. 26–27. Sawyer (1991), pp. 36.  ↩
  14. Niels Lund (2002), pp. 312. Ottonion Germany: The Chronicon of Thietmar of Merseburg. Translated and annotated by David A. Warner (Manchester: Manchester University Press, 2001), pp. 333.  ↩
  15. Sawyer (1991), pp. 37.  ↩
  16. Sawyer (1991), pp. 36.  ↩
  17. Anonymous, “The Anglo–Saxon Chronicle | 994.” The Avalon Project | Documents in Law, History and Diplomacy. Accessed November 22, 2017, Yale University.  ↩
  18. See ‘II Aethelred.’  ↩
  19. Niels Lund and Inge Skovgaard–Petersen, ‘Svend 1. Tveskæg,’ Den Store Danske. Gyldendal (2017). Last Accessed 10 December 2017.  ↩
  20. Snorri Sturlason, Heimskringla.  ↩
  21. See ‘Olaf Tryggvason.’ on The Viking Age Archive.  ↩
  22. See ‘Battle of the Svold’ on The Viking Age Archive.
    Theodericus monachus, An Account of the Ancient History of the Norwegian Kings. Translated by David and Ian McDougall (London, 1998). Scanned and proofread by Eric C. Knibbs, 2006. Viking Sources in Translation  ↩
  23. Svein H. Gullbekk (2012), pp. 162.  ↩
  24. Claus Krag, ‘Tyra Haraldsdatter.’ Norsk biografisk leksikon. Published 13 February 2009. Last Accessed 11 September 2018.
    According to Adam of Bremen, that is. It is possible that Sigrid Storråda had a Polish name. Contrarily, the Old Norse sources claim Sigrid was the daughter of Swedish chieftain Skoglar Toste. See: Sture Bolin, ‘Erik Segersäll,’ in: Swedish biographical dictionary. Last Accessed 16 December 2017.  ↩
  25. The Editors of Encyclopædia Britannica, ‘Otto III | Holy Roman Emperor,’ Encyclopedia Britannica Online, Last Accessed 02 August 2018.  ↩
  26. Ann Williams, ‘Thorkell the Tall and the bubble reputation: the vicissitudes of fame.’ In: Danes in Wessex: The Scandinavian Impact on Southern England, c. 800–c. 1100 . Edited by Ryan Lavelle and Simon Roffey (Barnsley: Oxbow Books, 2015), pp. 10–11.  ↩
  27. Levi Roach (2016), pp. 287–291.  ↩
  28. Niels Lund and Inge Skovgaard–Petersen, (2017).  ↩
  29. Levi Roach (2016), pp. 200.  ↩
  30. Niels Lund and Inge Skovgaard–Petersen, (2017).  ↩
  31. Foundation for Genealogy, ‘Svend Haraldsen,’ Last Accessed: 11 September 2018. FMG Project ↩
  32. JS (1962), pp. 27.
    Encomium (1949), pp. iv.
    Ottonion Germany (2001), pp. 332–334.  ↩

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