Suibne mac Cináeda (died 1034) was an eleventh-century ruler of the Gall Gaidheil, a population of mixed Scandinavian and Gaelic ethnicity.

This extension of power may have partially contributed to the destruction of the Kingdom of Strathclyde, an embattled realm which then faced aggressions from Dublin Vikings, Northumbrians, and Scots.

[13] The term appears to have been applied to a population of mixed Scandinavian and Gaelic ethnicity in the Hebrides and part of the former kingdom of Dál Riata.

[15] The leader of the Gall Gaidheil in the mid part of the century appears to have been a certain Caittil Find[16]—possibly identical to Ketill Flatnefr of Scandinavian saga tradition[17]—who may have been seated in the Hebrides.

[26] In fact, it is only by the twelfth century, during the floruits of that earliest members of the Gallovidian ruling family, that the Gall Gaidheil terminology came to be territorially confined within the boundaries of Galloway.

[33] In about 1031, Echmarcach was one of several northern kings who convened with, and possibly submitted to, Knútr Sveinnsson,[34] ruler of the Anglo-Scandinavian Empire comprising the kingdoms of Denmark, England, and Norway.

[40] The entire region would have thus stretched from the North Channel to Wigtown Bay,[41] and would have likely encompassed an area similar to the modern boundaries of Wigtownshire.

This could mean that the Rhinns was not part of the Gall Gaidheil territory during Suibne's floruit, and only came to be incorporated into these lands at a later date, perhaps the twelfth century.

[45][note 2] According to the thirteenth-century Historia Gruffud vab Kenan, a son of Sitriuc named Amlaíb was the grandfather of Gruffudd ap Cynan, King of Gwynedd.

[52][note 3] This suggests that the region encompassed within present-day Wigtownshire was regarded as distinct from the territory of the Gall Gaidheil in the eleventh century.

[75] One of the last recorded members of this kingdom's royal family was Owain Foel, King of Strathclyde, a man who lent military assistance to Máel Coluim against the Northumbrians in 1018.

[81][note 6] The claim by Historia Gruffud vab Kenan—that Sitriuc's son held power in the Rhinns amongst other regions—could be further evidence that the Cumbrians suffered from attacks by the Dubliners.

Such a move may explain the Scots' failure to immediately exploit their victory over the Northumbrians, and could indicate that Máel Coluim's resources were instead projected against the vulnerable Cumbrian realm.

If so, and if Máel Coluim indeed held power in the southern Hebrides as the Prophecy of Berchán seems to suggest, Echmarcach's realm may have encompassed Mann, the Rhinns, and only the Hebridean islands north of the Ardnamurchan peninsula.

[95] In the later stages of his career, Máel Coluim seems to have taken steps to remove potential threats to the royal succession, and in this context appears to have orchestrated the assassination of the son or grandson of a certain Boite mac Cináeda in 1033.