Blathmuine Ua Briain

Here is a family tree branch where we are descendants of, a Viking King’s son Sigurd (Slembedjakn) Slembe (Magnusson) married an Irish King’s daughter Blathmin ingen Muirchertach Ua Briain around 1100AD in an alliance-arranged marriage in Scotland.

Origins of the Galloway Kingdom, Scotland
Contrary to some popular conceptions, there is no evidence that Galloway was ever part of the Kingdom of Strathclyde. Thus Galloway (west of the Nith at least) lay outside of the traditional area claimed by the Kingdom of Alba, Strathclyde's successor state in the area. Galloway, often defined as all of the area to the south and west of the Clyde and west of the River Annan, lay outside of traditional Scottish territory. Though it formed part of the northern mainland of Britain, Galloway was just as much a part of the Irish Sea; part of that "Hiberno-Norse" world of the Gall-Gaidhelnlords of the Isle of Man, Dublin and the Hebrides.

For instance, the ex-King of Dublin and Man, Echmarcach mac Ragnaill, had the title Rex Innarenn ("King of Rhinns") attributed to him on his death in 1065. The western sections of Galloway had been firmly aligned with the Isle of Man, and Norse and Gaelic-Norse settlement names from the 10th and 11th centuries are spread all along the coastal lands of south-western "Scotland" and north-western "England."

In the late 11th century, the Norwegian King Magnus III Berrføtt ("Barelegs") led a campaign of subjugation in the Irish Sea world. In 1097, he sent his vassal, Ingimundr, to take control of the Kingdom(s) of Man and the Isles. However, when this man was killed, Magnus himself launched the first of his two invasions, the campaigns of 1098-1099and of 1102-1103. In the former campaign, he took control of the Western Isles of Scotland, and deposed King Lagmann of Man. (Incidentally, this campaign also brought him to Wales, where he killed the Earl of Chester and the Earl of Shrewsbury, who were at war with the Prince of Gwynedd). In this campaign, Magnus almost certainly brought Galloway under his suzerainty too. Magnus, moreover, gained the recognition of these conquests from the then-king of Alba, Etgair mac Maíl Coluim.

On his second campaign, Magnus went to Man, and with a huge fleet attacked Dublin and attempted to bring the submission of Muircertach mac Toirrdelbach, the Ui Briain King of Munster. The campaign resulted in an alliance between the two kings, and the arranged marriage of Magnus' son Siguðr to Muircertach's daughter Bláthmin. The alliance mitigated the threat of Domnall mac Lochlainn, King of Ailech, bringing stability to the Irish Sea world, and security to Magnus' new Irish Sea "Empire." However, it all went wrong when Magnus was killed on his way back to Norway on a minor raid in Ulster. Much of Magnus' work lay in ruins.