The Mormaer of Caithness was a vassal title mostly held by members of the Norwegian nobility based in Orkney from the Viking Age until 1350. The mormaerdom was held as fief of Scotland and the title was frequently held by the Norse Earls of Orkney, who were thus a vassal of both the King of Norway and the King of Scots. There is no other example in the history of either Norway or of Scotland in which a dynasty of earls owed their allegiance to two different kings.
The earliest reference to the title is however to that of a native Scots ruler, Donnchad, although the extent of the Scottish crown's influence so far north at the time, beyond the lands of the powerful Mormaers of Moray, is questionable. The Norse saga which mentions Donnchad does not provide a date, although the context suggests the early tenth century. Nonetheless, at least since the childhood of Thorfinn Sigurdsson in c. 1020, but possibly already several decades before, the Earls of Orkney were the controlling figures. In the Norse context the distinction between earls and kings did not become significant until the late 11th century and the Caithness mormaers therefore would have had considerable independence of action until that time.
The Pentland Firth, between Caithness and Orkney, was a stretch of water which divided the two earldoms but also united them, especially perhaps for the Norse, whose command of the seas was an important aspect of their culture. Indeed there are numerous incidents recorded in the Orkneyinga saga in which movement across these waters occurs as if the two polities were parts of a single political and cultural arena. Even in the mid-12th century it appears that a king of Norway - Eystein Haraldsson - had no difficulty in capturing Harald Maddadson, an Earl of Orkney, from his base in Thurso, Caithness. Meanwhile a Scottish king, David I, exercised control of both areas through promotion of the Scottish Church and other indirect rather than military means. In the 13th century, especially after the Norwegian defeat at the Battle of Largs and the subsequent Treaty of Perth in 1266, the distinctions hardened and the Firth became more like a "state border".
Sutherland was part of the Caithness mormaerdom for most of this title's history, but was "taken" by Alexander II from Magnus, the first "Angus" earl, and given to others for unknown reasons.
Most dates during the Norse period are approximate, but records become more detailed and historically accurate as the line of Norse jarls comes to an end. After the close of the Jarls' Saga on the death of Jon Haraldsson in 1230, the history of Caithness is "plunged into a darkness which is illuminated by very few written sources".
After the rule of Maol Íosa there was no mormaer of Caithness from c. 1350 to 1379. The title Earl of Caithness was granted to David Stewart, a younger son of the Scots king, and the mormaerdom effectively continued as an earldom from that point onwards.
Mormaers of Caithness The list is by necessity a fragmentary one, the archives being not fully preserved, the reigns of some supposed mormaers being not fully attested, and so forth. According to the Landnámabók, Thorstein Olafsson (fl c. 850-c. 880) and Sigurd Eysteinsson “conquered Caithness, Sutherland and Moray, and more than half of Argyll [and] Thorstein ruled over these territories as King”. There is no suggestion that Thorstein was beholden to any overlord although his son-in-law Donnchad is described as a "native earl".
Dates Mormaer NotesEarly 10th centuryDonnchad of Caithness Donnchad (or Dungadr) was married to Groa, daughter of Thorstein Olafsson.Mid 10th centuryUncertainThorfinn Torf-Einarsson, Donnchad's son-in-law having married his daughter Gruaidh, was a powerful Earl of Orkney from an unknown date until his death c. 963. However, there is no specific reference to him as a Mormaer of Caithness.978–980s?Skuli ThorfinnssonSon of Gruaidh and Thorfinn, supported by Kenneth II of Alba. Defeated in battle by his brother Ljot in the Dales of Caithness.980s? Ljot ThorfinnssonHis defeat of Skuli angered the Scots and MacBeth, the Mormaer of Moray, brought a large army north. They engaged in battle at Skitten Mire near Wick where Skuli was killed and Ljot died of his wounds shortly afterwards.980sHlodvir ThorfinnssonHe became Earl of Orkney after Ljot and on his death he was buried at "Ham in Caithness" suggesting that his writ extended that far, although there is no specific reference to any mainland title he may have had.991 to 1014Sigurd HlodvirssonEarl of Orkney, who "was powerful enough to defend Caithness against the Scots". Njal's saga describes his Scottish dominions as "Ross and Moray, Sutherland and the Dales", which last location may be a reference to Caithness. Earl Sigurd was killed at the Battle of Clontarf on 23 April 1014. 1014–c.1060Thorfinn Sigurdsson On the death of Sigurd, Thorfinn's older half-brothers divided Orkney and Shetland between them. King Máel Coluim of Scotland, his maternal grandfather, set Thorfinn up as ruler of Caithness and Sutherland with Scots advisors to rule for him.Mid-11th centuryMadadhan of CaithnessOrkneyinga saga mentions that "Muddan", who was a nephew of a King of Scots the saga calls Karl Hundason, became jarl of Caithness. He had not held this position long when he was killed by Thorkel "the Fosterer" Sumarlidason, an ally of Thorfinn Sigurdsson. Mid-11th centuryThorfinn Sigurdsson?Given the bullish remarks in the Orkneyinga saga about Earl Thorfinn's exploits - "conquering all the way south as far as Fife" - it is reasonable to suppose that he regained control of Caithness after the death of Muddan, with or without the support of the Scots royal house.To 1098Paul and Erlend Thorfinnsson?The sources are silent about what happened to the Caithness jarldom after Earl Thorfinn's death, although it is clear that his sons Paul and Erlend ruled as joint earls in Orkney at least.
Norwegian interlude
In 1098 Magnus Barefoot, King of Norway deposed the Thorfinnsson brothers as Earls of Orkney and set his 8 year old son Sigurd Magnusson up in their place. This was an unprecedented occurrence, probably intended as a permanent step. Magnus then conducted two vigorous campaigns in the Hebrides and Irish Sea region. It is likely that the de facto control of the mormaerdom was in his hands prior to his death during the second campaign in 1103 although "there does not seem to have been any intention on the Norwegian side" to formally take control of Caithness, which remained subject to the Scottish crown.
It is possible the native Celts regained the title at this time. in the late 11th or early 12th century, Ótarr son of Madadhan and brother-in-law of Haakon Paulsson is described as "jarl of Thurso". It is not certain that this second "Moddan of Dale" was a descendant of his earlier namesake, and there is no suggestion that Moddan himself was a jarl. Ótarr was the brother of Helga Moddansdóttir fl. 1015-23 and a "curiously shadowy figure".
Later Norse jarls
Dates Mormaer Notesc.1104 - c.1105Haakon PaulssonGrandson of Thorfinn Sigurdsson and made Earl of Orkney by the young King Sigurd of Norway he also claimed Caithness.c. 1105 - 1114 Magnus ErlendssonHaakon Paulsson's cousin who was joint Earl of Orkney from c. 1105 until his death on Egilsay at Haakon's hands."St. Magnus and his World", Foghlam Alba Caithness formed half of his estates.1114-1123Haakon Paulsson As sole Earl of Orkney he probably regained control of Caithness on the death of Magnus Erlendsson.1123-1128Harald HaakonssonNephew of Ótarr and son of Haakon Paulsson, he "held Caithness from the king of Scots".1128-1136Paul HaakonssonHalf-brother of Harald was also Earl or Orkney. He ruled jointly with Harald, then alone, then briefly with Rögnvald Kali Kolsson until his death at the hands of Sweyn Asleifsson and the descendants of Moddan of Dale. He and Earl Rögnvald divided his holdings between them, "which probably included Caithness". During the military events that preceded this division Earl Paul had gödings - allies - in Caithness but none in Shetland.1136-1151 (jointly 1139-58)Rögnvald Kali KolssonEarl of Orkney and likely ruler of Caithness for much of his tenure.1151-54Erlend HaraldssonSon of Harald Haakonsson. When Earl Rögnvald left Orkney in 1151 to go on a pilgrimage to the Holy Land, Erlend obtained half of his father's lands in Caithness from Malcolm IV of Scotland.1139-1206Harald "the Old" MaddadssonGrandson of Haakon Paulsson and son of Matad, Earl of Atholl. He became joint Earl of Orkney with Rögnvald as a child. During the "War of the Three Earls" 1151-58 Harald was captured from a base in Thurso by King Eystein Haraldsson of Norway aged only 18, then freed for a ransom. After the death of both Erlend and Rögnvald he became sole ruler of Orkney in 1158 until his own death in 1206.1198 Harald "the Younger" Eiriksson Grandson of Rögnvald Kali Kolsson. Half of Caithness was granted to him by king William the Lion but he died later that year near Wick in a military conflict with Harald Maddadsson, whose grip on Caithness then resumed.1206-1214David Haraldsson Son of Harald "the Old" he ruled jointly over Caithness and Orkney with his brother Jon.1214-1230Jon HaraldssonJointly with his brother David, then alone until he was murdered in Thurso.
After the failure of Harald the Younger, c.1200 William of Scotland then asked King of the Isles Rognvaldr Gudrodsson (Raghnall mac Gofraidh) to take Caithness on behalf of the Scottish Crown. Rognvaldr marched north, subduing the region and then returned to the Isles leaving three stewards in charge. Although not descended from previous Orcadian earls, Rognvaldr was related to these Norse magnates through his paternal grandfather's marriage to Ingibjorg, daughter of Haakon Paulsson. There is no evidence of his installation as a Mormaer of Caithness, only that he was appointed to administer the province. His tenure in Caithness seems to have been short-lived and once again Harald Maddadsson became the undisputed ruler of his northern holdings.
Angus and Strathearn rulers
Jon Haraldsson's son Harald had drowned in 1226 and as there were no male heirs two parties with a claim sought the jarldom from King Haakon Haakonsson of Norway. On their return to Orkney in the autumn of 1232 in a single ship the claimants and their supporters were all lost at sea. As early as 2 October of that year the Caithness title was claimed by a member of the family of the Earl of Angus and it was to this house that Caithness and Orkney were eventually granted.