Dubhghall mac Ruaidhrí (died 1268) was a leading figure in the thirteenth-century Kingdom of the Isles, on the West Coast of Scotland.

The careers of Dubhghall and his Clann Somhairle kinsman, Eóghan Mac Dubhghaill, exemplify the difficulties faced by the leading Norse-Gaelic lords in the Isles and along western seaboard of Scotland.

[35] This dramatic projection of Scottish royal authority may have also resulted in the king's establishment of the Clann Dubhghaill lordship of Argyll which appears on record not long afterwards.

[44] On the other hand, the family's position in the Isles may have stemmed from its marital alliance with the Crovan dynasty, an affiliation undertaken at some point before Ruaidhrí's apparent expulsion from Kintyre.

For example, the northern Hebridean islands of Lewis and Harris and Skye appear to have been held by the Crovan dynasty, then represented by the reigning Haraldr Óláfsson, King of Mann and the Isles.

[55] It is conceivable that Eóghan and Dubhghall sought kingship of the same jurisdiction that Hákon had awarded to Óspakr-Hákon about a decade before—a region which could have included some or all of the islands possessed by Clann Somhairle.

[80] Although the Scottish Crown appears to have attempted to purchase the Isles earlier that decade,[81] Alexander II launched an invasion of Argyll, in the summer of 1249, directed at the very heart of the Clann Dubhghaill lordship.

[84] In the course of this offensive, Alexander II demanded that Eóghan renounce his allegiance to Hákon, and ordered him to hand over certain mainland and island fortresses.

[92] For instance, a particular entry preserved by the Icelandic annals states that, within the very year that Eóghan was forced from Argyll by the Scots, Dubhghall himself "took kingship" in the Isles.

[95] In fact, Eóghan's actions of the following year—when he and Magnús Óláfsson, a member of the Crovan dynasty, unsuccessfully attempted to seized control of Mann—could further indicate he was in dire straits.

[96] Magnús,[97] Dubhghall, and Eóghan were back in Scandinavia in 1253,[98] as Hákonar saga Hákonarsonar reveals that the latter two took part in the Norwegians' royal campaign against the Danish Crown.

[101] However, the record of Dubhghall holding kingship as early as 1249, coupled with Eóghan's attempt to gain control of Mann in 1250, and the fact that both men were identified as kings whilst campaigning with the Norwegians royal forces in 1253, could indicate that Hákon had originally intended for both men to hold kingship, possibly with Dubhghall in the Hebrides and Eóghan on Mann.

No doubt as a result of this spoliation, the sources further reveal that Jordan d'Exeter, the English Sheriff of Connacht, pursued Dubhghall's fleet and was slain along with many of his men in the culminating clash.

[110][note 6] The marital alliance between Aodh and Dubhghall was conducted at the main port within Brian's realm, a site indicating that the union—along with the assembly and naval operations of the previous year—was part of a carefully coordinated plan to tackle English power in the north west of Ireland.

[134] In 1262, the year after yet another failed attempt by the Scottish Crown to purchase the Isles, Hákonar saga Hákonarsonar reports that the Scots lashed out against the Islesmen in a particularly savage attack upon the inhabitants of Skye.

[135] Thus provoked, Hákon assembled an enormous fleet—described by the Icelandic annals as the largest force to have ever set sail from Norway[136]—to reassert Norwegian sovereignty along the north and west coasts of Scotland.

[139][note 12] In July 1263, this armada disembarked from Norway, and by mid August, Hákon reaffirmed his overlordship in Shetland and Orkney, forced the submission of Caithness, and arrived in the Hebrides.

[162] In fact, the saga reveals that Hákon had previously received overtures from the Irish, requesting the Norwegians combat the English in exchange for overlordship of Ireland.

[168] Certainly, Aodh's relationship with Clann Ruaidhrí,[169] and his apparent overtures to the Norwegian Crown, illustrate the radical measures that certain Irish lords were prepared to take in order to overcome English dominance in Ireland.

[168] The fact that Dubhghall, Ailéan, and Magnús, were unequivocal supporters of the Norwegian cause against Scottish encroachment in the Isles, and simultaneously involved in Irish affairs, suggests that they were the unidentified men that Alexander attempted to prevent from entering Ireland just prior to the battle at Downpatrick.

[173] Not only did Hákon fail to break Scottish power, but Alexander III seized the initiative the following year, and oversaw a series of invasions into the Isles and northern Scotland.

Recognising this dramatic shift in royal authority, Magnús submitted to Alexander III within the year,[174] and in so doing, symbolised the complete collapse of Norwegian sovereignty in the Isles.

[176] In fact, the thirteenth-century Magnúss saga lagabœtis reveals that he continued to resist, and conducted military operations against the Scots in Caithness.

Specifically, with the conclusion of the Treaty of Perth in July, Hákon's son and successor, Magnús Hákonarson, King of Norway, formally resigned all rights to Mann and the islands on the western coast of Scotland.

When the kindred finally reemerges in 1275, it is in the person of Dubhghall's brother, Ailéan, a man who was by then a prominent Scottish magnate,[194] and representative of Clann Ruaidhrí.