Thorfinn the Mighty
|Earl of Orkney|
|Title held||c. 1016 to c. 1065. Jointly with Brusi Sigurdsson and Einar Sigurdsson to 1020, with Brusi to 1031, alone to 1036, with Rögnvald Brusason 1036 to 1046, alone to c. 1065|
|Successor||Paul and Erlend Thorfinnsson|
IssuePaul and Erlend Thorfinnsson
|Native name||Þorfinnr inn riki - "Thorfinn the Mighty"|
|Noble family||Norse Earls of Orkney|
|Mother||A daughter of Máel Coluim II of Scotland|
Thorfinn Sigurdsson (1009?–c. 1065), called Thorfinn the Mighty, was an 11th-century Earl of Orkney. He was one of five brothers (with Brusi, Sumarlidi, Einar and Hvelp), sons of Earl Sigurd Hlodvirsson. Thorfinn was the youngest of the five known sons, but the only son of Sigurd's marriage to a daughter of Máel Coluim II of Scotland. His elder half-brothers Einar, Brusi and Sumarlidi survived to adulthood, while a brother called Hundi ("the Dog") or Hvelp ("the Whelp") died in Norway, a hostage at the court of King Olaf Trygvasson. Thorfinn married Ingibiorg Finnsdottir, daughter of Finn Arnesson, Jarl of Halland.
The Heimskringla of Icelandic historian Snorri Sturluson, and the anonymous compiler of the Orkneyinga Saga, wrote that Thorfinn was the most powerful of all the earls of Orkney. He is said to have been earl for seventy-five years and ruler of nine earldoms in Scotland, of the Hebrides, and of part of Ireland. A sizeable part of the account in the Orkneyinga Saga concerns his wars with a "King of Scots" named Karl Hundason whose identity is very uncertain.
- 1 Sources
- 2 Background
- 3 Joint rule
- 4 War with Karl Hundason
- 5 Joint rule with Rognvald
- 6 Pilgrimage
- 7 Death
- 8 Interpretations
- 9 References
- 10 Further reading
The sources for Sigurd's life are almost exclusively Norse sagas, none of which were written down at the time of the events they record. The main sources are St Olfa's saga in the Heimskringla and the Orkneyinga Saga, which was first compiled in Iceland in the early 13th century and much of the information it contains is "hard to corroborate".
Thorfinn was the youngest of the five known sons of Earl Sigurd Hlodvirsson, but the only son of Sigurd's marriage to a daughter of Malcolm II (Máel Coluim mac Cináeda). His elder half-brothers Einar, Brusi and Sumarlidi survived to adulthood, while another brother called Hundi died in Norway, a hostage at the court of King Olaf Trygvasson.
Earl Sigurd was killed at the Battle of Clontarf on 23 April 1014. Before setting out for Ireland, he had sent Thorfinn, then aged five, to be fostered by his maternal grandfather, the King of Scots. When the news of Sigurd's death came, Thorfinn's older half-brothers divided Orkney and Shetland between them. King Máel Coluim set Thorfinn up as ruler of Caithness and Sutherland with Scots advisors to rule for him. Earl Sigurd had also been a ruler of the Suðreyar but these holdings appear to have escaped control of the earls of Orkney at the time of his death or shortly thereafter.[Note 2]
The Orkneyinga Saga gives this description of Thorfinn:
He was unusually tall and strong, an ugly-looking man with a black head of hair, sharp features, a big nose and bushy eyebrows, a forceful man, greedy for fame and fortune. He did well in battle, for he was both a good tactician and full of courage.
With Einar and Brusi
Joint earldoms were a frequent feature of the Norse earldom of Orkney but the Orkneyinga saga is less than explicit about how these shares were divided up geographically. It is possible that Brusi's share, described as the "northernmost part of the isles", was those islands lying north of the Orkney mainland, that Einar's was originally the east Mainland and the south isles and that Sumarlidi's was the west Mainland. However, it is also possible that Brusi's share was Shetland, which formed part of the earldom throughout the Norse period. This possibility is supported by a later reference to his son Rögnvald as "Lord of the Shetlanders" and Thompson (2008) is in "no doubt " that Shetland was in Brusi's possession.
Sumarlidi died in his bed not long after his father and Einar took his share, ruling two-thirds of the earldom with the remaining third held by Brusi. Einar soon became unpopular, demanding heavy taxes and frequent military service from the farmers, and gaining little booty on his raids. He was, the saga says, "a great bully", whereas Brusi was "well liked by everyone".
The farmers of the isles opposition to Einar's rule were led by Thorkel Amundason and, in danger of his life, he fled to Thorfinn's court in Caithness. He became his foster-father, hence his by-name, "Thorkel Fosterer". On Sumarlidi's death c. 1018 the disposition of his third share in Orkney and Shetland became a matter of dispute when Thorfinn claimed it as his. While Brusi was willing to grant it to him, Einar, who was "ruthless and grasping, a hard and successful fighting man" and somewhat like Thorfinn in temprament was not. Einar and Thorfinn began raising an army to settle matters by force, but Earl Brusi made peace between them by raising his own men to come betwen them and then persuading Einar to give Thorfinn what he asked for. It was also agreed that that on the death of either Brusi or Einar that the surving brother would inherit the other's share.
Thorfinn appointed Thorkel Fosterer as his tax-gatherer in the islands, but Einar had not forgotten their earlier dispute and Thorkel again left the islands in fear of his life, returning to Caithness. Thorkel then travelled to Norway with Thorfinn's support, to meet with King Olaf Haraldsson. He was well received there, for Olaf bore his own grudge against Einar for the killing of his comrade Eyvind Aurochs-Horn some years earlier. Olaf invited Thorfinn to Norway, and he too was welcomed to Olaf's court. Thorfinn and Thorkel returned to Orkney, to find Einar raising an army against them. Brusi again made peace between them, and it was agreed that Einar and Thorkel would make peace and entertain one another to a feast.
In October 1020 Einar attended Thorkel's hall at Hlaupandanes in Deerness in a sour mood. On the last day of the feast Thorkel was supposed to travel with Einar for the reciprocal event but the former's spies reported that ambushes were in place en route. Thorkel therefore delayed his departure, leaving Einar to wait for his arrival by the fire in his great hall. Thorkel arrived by stealth, walked into the hall with one of his men and they killed Einar. Thorkel then escaped to Norway.
The death of Einar did not end the dispute over Sumarlidi's third of the islands. Brusi considered that it belonged to him, as he and Einar had agreed when Thorfinn received a third of the islands. Thorfinn thought that the islands should be divided equally. However, Thorfinn could count on the assistance of his grandfather, King Máel Coluim, while Brusi had only the forces he could raise from his share of the islands, making any conflict a very unequal one. Brusi went to Norway, to the court of King Olaf Haraldsson, to have Olaf judge the dispute, and Thorfinn joined him there. Brusi surrendered the earldom to Olaf, who granted a third to each brother, and kept a third for himself. Thorfinn attempted to use his relationship with the King of Scots as a means to avoid acknowledging Olaf as his overlord in Orkney and Shetland, but Olaf threatened to appoint another to rule Thorfinn's share. Following Thorkel the Fosterer's advice, Thorfinn agreed to Olaf's settlement. After Thorfinn left Norway, Olaf gave Brusi the disputed third to rule on his behalf, but kept Brusi's son Rognvald in Norway as a hostage. These events are dated to 1021.
The arrangement with Olaf Haraldsson lasted while Olaf was king. But in 1030 he was overthrown by the Danish king Cnut the Great at the Battle of Stiklestad. After this Orkney was raided by Norwegians and Danes and Brusi agreed to give King Olaf's third to Thorfinn in return for Thorfinn seeing to the defence of the islands. This agreement lasted until Brusi's death, some time between 1030 and 1035. After that, Thorfinn was sole ruler of the Orkney earldom as a vassal of the King of Norway and Earl of Caithness responsible to the King of Scots.
War with Karl Hundason
The Orkneyinga Saga says that a dispute between Thorfinn and Karl Hundason began when the latter became "King of Scots" and claimed Caithness. In the war which followed, Thorfinn defeated Karl in a sea-battle off Deerness at the east end of the Orkney Mainland. Then Karl's nephew Mutatan or Muddan, appointed to rule Caithness for him, was killed at Thurso by Thorkel Fosterer. Finally, a great battle at "Torfness" (probably Tarbat Ness on the south side of the Dornoch Firth) ended with Karl defeated and fugitive or dead. Thorfinn, the saga says, then marched south through Scotland as far as Fife, burning and plundering as he passed.
Joint rule with Rognvald
Thorfinn ruled alone in Orkney until the return of his nephew Rognvald Brusason in about 1037. Rognvald had received the favour of King Magnus the Good, who granted him Brusi's share of the islands and the third which Olaf Haraldsson had claimed after Einar's death. Thorfinn agreed to this division, but presented the transfer of the third claimed by the Norwegian king as a gift to Rognvald in return for aid in Thorfinn's wars in the Hebrides and the Irish Sea.
King Sigtrygg Silkbeard had died in 1035 or 1036, and the kingship in Dublin had come to Echmarcach mac Ragnaill, who was challenged by Imar mac Arailt and driven out in 1038. This instability in Dublin can only have helped Thorfinn and Rognvald, who raided far and wide and established their rule over some part of the lands around the Irish Sea. They are said to have won a major victory beside Vattenfjord, perhaps Loch Vatten on the west coast of the Isle of Skye. The Earls are said to have raided in England, with mixed success.
At some point around 1034 Thorfinn is said to have conquered the Hebrides and he is likely to have been a de facto ruler of the Kingdom of the Isles, in whole or in part until his death although the assumption of Echmarcach mac Ragnaill as "King of Mann" from 1052–1061 may have encroached on his territories.[Note 3]
In time, Thorfinn and Rognvald fell out. The vivid account of the war between Thorfinn and Rognvald in the Orkneyinga Saga which survives may well be only a part of a much longer saga now lost. Their enmity arose with the arrival of Kalf Arnesson and his followers in Orkney. Kalf was the uncle of Thorfinn's wife Ingibiorg Finnsdottir, and had left Norway to escape King Magnus Olafsson. Rognvald, with Kalf's brothers, had shared Magnus's exile in Kievan Rus under the protection of Prince Yaroslav the Wise, and the saga says that when Kalf came to Ladoga to invite Magnus back to Norway, Rognvald almost attacked him. Thorfinn, it is said, found hosting Kalf and his men a burden, and in time asked Rognvald to return the third of the earldom "which had once belonged to Einar Wry-Mouth". Rognvald refused, saying that it was for King Magnus to settle matters. Thorfinn began raising an army, and Rognvald's islanders were unwilling to fight Thorfinn, so Rognvald sailed to Norway where King Magnus supplied him with ships and men. He returned to the islands, facing Thorfinn and Kalf Arnesson in a sea battle which Arnor the skald commemorated in verse. The battle went Rognvald's way to begin with, but in the end he was defeated and forced again to seek refuge with King Magnus.
King Magnus offered to fit out another expedition for Rognvald, but he decided to take just one ship and a picked crew. He sailed to Shetland in winter, and learning that Thorfinn was staying on a farm on the Orkney Mainland with only a few men, he set out at once to attack him. Rognvald's men surprised Thorfinn, and set the farm ablaze. The saga says that Thorfinn had to break down a wall and escape, carrying his wife in his arms, flying south to Caithness for safety. Rognvald ruled in Kirkwall over the winter, believing Thorfinn dead, but in the spring, while staying on Papa Stronsay, Thorfinn and his men turned the tables, taking Rognvald by surprise, just as he had surprised Thorfinn. Rognvald escaped the house, but was tracked down, given away by the barking of his lap dog, and killed by Thorkell Fosterer.
The Orkneyinga Saga offers this assessment of Rognvald:
Everyone agrees that of all the Earls of Orkney he was the most popular and gifted, and his death was mourned by many.
Even with Rognvald dead, Thorfinn was not entirely secure. The saga recounts an attempt to make peace with Magnus Olafsson, who had sworn vengeance for the death of his men in Thorfinn's attack on Rognvald. Magnus was at war with the Danish king Sweyn Estridsson, and died before he could take any action. Magnus's uncle and successor, Harald Sigurdsson, better known as Harald Hardrada, was more friendly towards Thorfinn, and made a peace, accepting Thorfinn's gifts.
Thorfinn had two sons, both by his wife Ingibiorg, and unlike a number of his predecessors he appears to have married only once. Furthermore, unlike his brothers, Thorfinn had been raised as a Christian. Among the signs of the changes in Orkney society was Thorfinn's pilgrimage to Rome, which took place after his meeting with Harald Sigurdsson, probably beginning in 1048. The saga says that he travelled through Saxony, meeting with Emperor Henry (Henry III) on the journey. It is thought that he also met with Archbishop Adalbert of Hamburg-Bremen.
As a result of Thorfinn's request, it appears that the first Bishop of Orkney was appointed at about this time. Named Thorulf, he may have been the same person as "Roolwer", Bishop of the Isles. The original seat of the bishops of Orkney was Thorfinn's Christ Kirk at Birsay, or perhaps the Brough of Birsay, where he had his residence in his later years.
The Orkneyinga saga dates Thorfinn's death no more precisely than placing it "towards the end" of Harald Sigurdsson's reign, which is far from exact. Thorfinn returned from Rome in around 1050 and Harald Sigurdsson died at the battle of Stamford Bridge in 1066, leaving a period of perhaps a decade in which Thorfinn's death might be placed. 
Thorfinn was buried in the grounds of St. Magnus Church, Birsay, Mainland Orkney. He is known to history as Thorfinn the Mighty, and at his height of power, he controlled all of Orkney and Shetland, the Hebrides, Caithness and Sutherland, and his influence extended over much of the north of Scotland. The Orkneyinga saga also makes a grander and more unlikley claim – that he controlled a total of seven earldoms in Scotland.
The saga states that Thorfinn's grandfather was "King Malcolm of Scotland" and it is often assumed that this was Malcolm II. However, both the Irish annals for this period and the Norse sagas have a tendency to refer to a "king of Scots" when discussing a regional chief or mormaer. Woolf (2007) suggests that this Malcolm may either have been a son of the Pictish Mormaer of Moray Mael Brigte or, as elsewhere in Icelandic literature, Melkólmr was simply used as a generic name, in this case for for Scottish royalty.[Note 4]
The chronology of Thorfinn's life is problematic, the dating his assumption of the earldom being an example. The Heimskringla states that Thorfinn was 5 years old when his father Sigurd was killed at Clontarf, reliably dated to 1014. "When Thorfinn came of age he asked Earl Einar for a third of the islands" and it is clear from the text of the Orkneyinga saga that Einar, Brusi and Thorfinn were joint earls for a period. Muir (2005) is clear that Einar died in October 1020 but if Thorfinn was five years old in 1014 this would have made him only eleven by then. A rather earlier birthdate for Thorfinn is thus implied, with a coming of age c. 1016 at about the time of Sumarlidi's death. Similarly, Thorfinn is often stated as dying c. 1064, although Woolf (2007) states that "there is no reason why a date in the late 1050s is not just as credible."
A related issue is the actions of his widow. Historians offering a later date for Thorfinn's death have proposed that Malcolm Canmore married a postulated daughter of Thorfinn named Ingibiorg rather than his widow. If a date in the early 1050s is presumed, then Máel Coluim could well have married Thorfinn's widow as the saga suggests.
Duncan argued that Máel Coluim mac Donnchada came to marry Thorfinn's widow because he spent some or all of the period of Mac Bethad's reign in Orkney or Caithness at Thorfinn's court. Thorfinn and Máel Coluim were both descendants of Malcolm II, daughter's son and daughter's grandson respectively, and both had good reason to be hostile to Mac Bethad and his kinsmen, the Kings of Moray. Malcolm Canmore became king of Scots c. 1058 and the Orkneyinga Saga records that he and Ingibiorg had a son, Duncan II who was later king. There is some circumstantial evidence that Ingibiorg may have backed Malcolm's claim to the kingship which adds further weight to a slighly earlier death date for Thorfinn, although the evidence for her marriage to Malcolm is not entirely convincing.
Who was Karl Hundason?
The identity of Karl Hundason, unknown to Scots and Irish sources, has long been a matter of dispute. His existence rests solely on the Orkneyinga saga, and more particularly on those elements of Arnór jarlaskáld's Þórfinnsdrápa which are preserved within it.[Note 5]
Robertson (1862) proposed that Hundason should be identified with Duncan I. Skene (1902) suggested that Karl (or Kali) Hundason should be identified with "Malcolm MacKenneth", a son of Kenneth III. Another candidate is Macbeth whose father may be called "jarl Hundi" in Njál's saga. Woolf (2007) proposes that Hundason, rather that being some hitherto unknown Scots king, was the son of Thorfinn's brother Hundi. However, Thomson (2008) notes that both the Orkneyinga saga and St Olaf's saga suggest he only lived "a short while" and was unlikely to have had a son himself. Anderson (1990) suggested that this is "a fabulous story" and concluded that "[n]o solution to the riddle seems to be justified".
Muir (2005) points out that a literal translation of "Karl Hundisson" is "peasant son-of-a-dog", an insult that would have been obvious to Norse-speakers hearing the saga and that "we can assume this wasn't his real name". The implication is that there is no purpose in seeking phonetic parallels with known Scots personages. Thomson points out that both "Karl" and Hundi" are names used in other contexts without disparaging intentions although the combination is otherwise unknown.
Thomson (2008) notes that the war with Hundasson seem to have taken place between 1029 and 1035 and that the Annals of Ulster record the violent death of Gillacomgain, son of Mael Brigte and Mormaer of Moray in 1032. He too is thus a candidate for Thorfinn's Scots foe—and the manner of his death by fire bears comparison with Arnór's poetic description of the aftermath of the battle at Torfness.
Whoever Karl son of Hundi may have been, it appears that the saga is reporting a local conflict with a Scots ruler of Moray or Ross:
[T]he whole narrative is consistent with the idea that the struggle of Thorfinn and Karl is a continuation of that which had been waged since the ninth century by the Orkney earls, notably Sigurd Rognvald's son, Ljot, and Sigurd the Stout, against the princes or mormaers of Moray, Sutherland, Ross, and Argyll, and that, in fine, Malcolm and Karl were mormaers of one of these four provinces.[Note 6]
It is therefore entirely possible that Thorfinn's campaign was not fought against the Scottish crown as such but that rather the Scots may have been his allies in a struggle they both had against the power of Moray.
Christianity, morality and power
The joint rulership of earls was a recurring theme in the period up to 1214 and was "inherently unstable and usually ended in violence". Thomson (2008) identifies these family feuds as being the main theme of the Orkneyinga saga, culminating in the martyrdom of St Magnus c.1115, and that the saga writer regularly emphasises the doom of "kin-slaying". In this case the Sigurdsson brothers do not assassinate one another, but rather Thorkel Fosterer becomes an intermediary, killing both Einar rangmunnr and, at a later date, Rögnvald Brusasson on behalf of Thorfinn.
It is also clear that there is a moral element to the tale, with Brusi cast as the peacemaker who is father to the noble Rögnvald and who stands in contrast to his greedy half-brother. Notwithstanding these roles, Thorfinn's Christianity is emphasised in the saga materials. The Norse in the Northern Isles would have been strongly influenced by the neighbouring Christian countries and it is likely that marriages to individuals from such polities would have required baptism even before his time. Informal pagan practice was likely widespread throughout his earldom, but the weight of archaeological evidence suggests that Christian burial was widespread in Orkney even during the reign of Sigurd Hlodvirsson, Thorfinn's father.
Furthermore, Brusi has a relatively minor role to play compared to Thorfinn "the Mighty", whose conquests included expansion well into north mainland Scotland and whose rule may have marked the zenith of Scandinavian influence in Scotland. As there were only seven Scottish earldoms in total, the sagas claim that he held this many seems to suggest that he was King of Scots. However, this may reflect a royal pretension of his, derived from maternal descent from a king Malcolm as such descent, according Bede, was a strong right to Pictish throne, the lands of Moray and Alba ('seven earldoms').
Relations with Norway
The role of the Norwegain crown is another recurring aspect of the saga. Crawford (1987) observes several sub-themes: "submission and of overlordship; the problem of dual allegiance and the threat of the earls looking to the kings of Scots as an alternative source of support; the Norwegian kings' use of hostages; and their general aim of attempting to turn the Orkney earls into royal officials bound to them by oaths of homage, and returning tribute to them on a regular basis." King Olaf was a "skilled practitioner" of divide and rule and the competing claims of Brusi and Thorfinn enabled him to take full advantage.
Thorfinn's journey in 1020 is the first occasion on which an earl of Orkney is known to have visited the royal court in Norway and the Icelandic Annals have little to say about Orkney. However, under the year 1021 it is said "Earl Thorfinn and earl Brusi, Sigurd's sons, gave the Orkneys into the power of King Olaf." Although the saga writer paints a vivid and plausible picture of the scene, this "merely tell us that the thirteenth-century saga writer knew his Orkney traditions and the recurring factors which did indeed come to the fore on occasions during the thirteenth century when the kings and earls fought or negotiated from their related positions of strength".
Finally, Thorfinn's death may have created a power vaccuum and been a cause of the invasion of the Irish Sea region nominally led by King Harald harðraði 's young son Magnus Haraldsson dated to 1058.
The basis of Dorothy Dunnett's 1982 novel King Hereafter is a point made by W. F. Skene, who noted that the historical sources which mention Thorfinn do not refer to Mac Bethad, and vice versa. Pursuing this idea, Dunnett wrote the novel on the premise that Mac Bethad and Thorfinn were the same person.
In his historical novel MacBeth the King Nigel Tranter portrayed Thorfinn as a half-brother of Macbeth, with a common mother. It also seeks to tie together the pilgrimages made to Rome by both, as one and the same.
?Sigurd Hlodvirsson of Orkney?
|Mormaer of Caithness
?Madadhan of Caithness?
|Earl of Orkney
with Einar Sigurdsson −1020
with Brusi Sigurdsson −c.1030
with Rögnvald Brusason 1037 – c.1045
Paul and Erlend Thorfinnsson
- The Heimskringla states that Thorfinn was 5 years old when his father Sigurd was killed at Clontarf, reliably dated to 1014 but see main text for a discussion of the chronological issues.
- Crawford (1987) states that there was a possible "collapse of the earls' control in the west" following the Battle of Clontarf although Thomson (2008) suggests Sigurd's son Einar rangmunnr may have inherited his father's territories in the Hebrides. There is no specific evidence that Einar ever claimed to be a ruler of the Suðreyar. He died c. 1025 and a late twelfth century Norwegian text claims that Håkon Eiriksson ruled the isles from 1016–1030.
- Echmarcach mac Ragnaill may have "ruled Dublin and the Isles intermittently until 1061" although there appears to be no specific evidence of his presence in or around the Scottish islands.
- The Irish Annals of Tigernach for the year 1029 refer to "Malcolm, king of Scotland, the son of Maelbrigte, son of Ruadri" who died in that year, which is clealry a description of the Mormaer of Moray rather than Malcolm II.
- Arnór's poetry is quoted verbatim in the saga, interspersed with various embellishments in the narrative. Arnór was in Orkney at or about the time of this conflict and it is he who describes Thorfinn's foe as "Karl" and "lord of the Scots". It is the saga writer who adds the patronymic "Hundasson".
- There were only two Earls of Orkney named Sigurd. Taylor idenitifies Sigurd "the Stout" Hlodvirsson but the earlier Sigurd ("the Mighty") was Rognvald Eysteinsson's brother, not his son.
- Muir (2005) p. 45
- Muir (2005) Preface: Genealogical table of the Earls of Orkney.
- Muir (2005) p. 53
- Heimskringla. "Chapter 99 - History Of The Earls Of Orkney".
- Woolf (2007) p. 243
- Magnusson, Magnus (2000). Scotland:The Story of a Nation. Harper Collins. p. 733. ISBN 9780871137982.
- Woolf (2007) p. 242
- Orkneyinga Saga c. 12; St. Olaf's Saga c. 96. Other versions are given in Anderson (1990) pp. 507–511.
- Orkneyinga Saga, cc. 12–13
- Gregory (1881) p. 5
- Crawford (1987) p. 71
- Thompson (2008) p. 73
- Woolf (2007) p. 246
- Orkneyinga Saga, c. 20; St. Olaf's Saga, c. 96; Anderson (1990) pp. 542–543
- Thompson (2008) pp. 70-73
- Muir (2005) pp. 44-45, "he died in his bed not long after his father's death" and is not referred to in an incident dated to 1018.
- Orkneyinga Saga, c. 13; St Olaf's Saga, c. 97.
- Orkneyinga Saga c. 12-13 p. 38
- Muir (2005) pp. 44-46
- Orkneyinga Saga cc. 14–15.
- Anderson (1990) p. 554
- Thompson (2008) p. 74
- Muir (2005) p. 46
- Orkneyinga Saga c. 16
- St Olaf's Saga, cc. 98–99.
- Orkneyinga Saga, cc. 17–19; St. Olaf's Saga, cc. 100–102.
- Muir (2005) p. 48
- Orkneyinga Saga, c. 19 pp. 49-50; St. Olaf's Saga, c. 102
- Roberts, John Lenox (1997), Lost Kingdoms: Celtic Scotland and the Middle Ages, Edinburgh University Press, p. 22, ISBN 978-0-7486-0910-9
- Orkneyinga Saga c. 20
- Orkneyinga Saga, c. 22
- Crawford (1987) p. 74 suggests that Vattenfjord might also refer to Waterford. Anderson, ESSH, p. 585, note 2
- Orkneyinga Saga c. 22
- Woolf (2007) p. 245
- Duffy (1992) p. 100
- Downham (2007) p. 171
- Downham (2007) p. 198
- Anderson (1990) p. 585, note 2.
- Orkneyinga Saga c. 25
- Orkneyinga Saga c. 21.
- Orkneyinga Saga c. 26
- Orkneyinga Saga, c. 25–29
- Orkneyinga Saga, c. 29.
- Crawford (1987) pp. 80–81, who suggests that Adam of Bremen's report of a "legate" from Orkney probably refers to Thorfinn himself.
- Orkneyinga Saga cc. 30–31
- Woolf (2007) p. 309
- Crawford (1987) pp. 81–82; Watt (1994) p. 109–110
- Orkneyinga Saga cc. 31–32
- Orkneyinga Saga, cc. 32–33
- Orkneyinga Saga c. 32
- Orkneyinga Saga, c. 33.
- Orkneyinga Saga c. 13
- Thomson (2008) p. 77
- Duncan (2002) p. 42.
- Woolf (2007) p. 267
- Crawford (1987) p.67, fig. 21, & p. 74; Donaldson, pp. 57–58; Duncan, pp. 41–43.
- Duncan, pp. 38–42. Note also Richard Oram's change of view between The Canmores (2002) p. 11, and his David I (2004) pp. 18–20
- Woolf (2007) p. 269
- Thomson (2008) p. 76
- Robertson (1862) II pp. 477–479
- Skene (1902) 1 c. 5
- Williams, Smyth & Kirby (1991) pp. 106–107
- Crawford (1987) p. 72
- Woolf (2007) pp. 309–310.
- Thomson (2008) pp. 75-77
- Anderson (1990) p. 576, note 7
- Muir (2005) p. 47
- Thomson (2008) p. 79
- Taylor (1937) p. 338; see also Crawford (1987) pp. 71–74.
- Crawford (1987) p. 54
- Thomson (2008) p. 80
- Thomson (2008) p. 58
- Orkneyinga Saga c. 29.
- Woolf (2007) p 311
- Thomson (2008) p. 64
- Crawford (1987) pp. 76-77
- Crawford (1987) pp. 78
- Donaldson (1990) pp. 56–57
- Anon. Orkneyinga Saga: The History of the Earls of Orkney. Translated by Pálsson, Hermann and Edwards, Paul Geoffrey (1981) Penguin Classics. ISBN 0-14-044383-5
- Sturluson, Snorri Heimskringla: History of the Kings of Norway, tr. Lee M. Hollander (1992) Reprinted University of Texas Press, Austin. ISBN 0-292-73061-6
- Anderson, Alan Orr (1990) Early Sources of Scottish History A.D 500–1286, volume 1. Reprinted with corrections. Paul Watkins, Stamford. ISBN 1-871615-03-8
- Crawford, Barbara, Scandinavian Scotland. (1987) Leicester University Press, Leicester. ISBN 0-7185-1282-0
- Donaldson, Gordon (1990) A Northern Commonwealth: Scotland and Norway. Saltire Society, Edinburgh. ISBN 0-85411-044-5
- Downham, Clare (2007) Viking Kings of Britain and Ireland: The Dynasty of Ívarr to A.D. 1014. Edinburgh. Dunedin Academic Press. ISBN 978-1-903765-89-0
- Duffy, Seán (1992). "Irishmen and Islesmen in the Kingdom of Dublin and Man 1052–1171". Ériu (43): 93–133. JSTOR 30007421.
- Duncan, A.A.M. (2002) The Kingship of the Scots 842–1292: Succession and Independence. Edinburgh University Press, Edinburgh. ISBN 0-7486-1626-8
- Gregory, Donald (1881) The History of the Western Highlands and Isles of Scotland 1493–1625. Edinburgh. Birlinn. 2008 reprint – originally published by Thomas D. Morrison. ISBN 1-904607-57-8
- Muir, Tom (2005) Orkney in the Sagas: The Story of the Earldom of Orkney as told in the Icelandic Sagas. The Orcadian. Kirkwall. ISBN 0954886232.
- Robertson, (1862) Scotland under her early kings,
- Skene, W. F. (1902) The Highlanders of Scotland. Eneas MacKay. Stirling.
- Taylor, A.B. (1937) "Karl Hundason: King of Scots" in the Proceedings of the Society of Antiquaries of Scotland. LXXI pp. 334–340.
- Watt, D.E.R. (Autumn 1994) "Bishops in the Isles before 1203" in The Innes Review. XLV No. 2. ISSN 0020-157X
- Williams, Ann; Smyth, Alfred P.; & Kirby, D. P. (1991) Biographical Dictionary of Dark Age Britain. Psychology Press.
- Woolf, Alex (2007) From Pictland to Alba, 789–1070. Edinburgh. Edinburgh University Press. ISBN 978-0-7486-1234-5
- Kingship and Unity by G W S Barrow. Edinburgh University press – ISBN 0-7486-0104-X