Óttar of Dublin

Over a number of centuries its members were active throughout the Irish Sea zone, often in conjunction with the Uí Ímair, from Caithness in the far north of Scotland to Cork in the south of Ireland.

[7] Contemporary annals suggest that Óttar was co-king with Ragnall mac Torcaill, until Ragnall was killed in a battle against the forces of Midhe (Meath) in 1145 or 1146: "A slaughter was made of the foreigners of Ath-cliath [Dublin] by the people of East Meath, where two hundred persons were slain, together with Raghnall Mac Torcaill, Mormaer of Ath-cliath, and Jufraigh, and many others of their chieftains.

[1] He was married to Helga daughter of Tolokunger, a Danish commander, and was the father of Thorfinus filius Oter, who was described as the most powerful jarl (princeps) in the Western Isles.

'[12] Óttar, the variant Irish spelling Otir is used, appears as a character in The Summer of the Danes by Ellis Peters in the Brother Cadfael series.

The book uses Cadwaladr ap Gruffydd's attempt to reclaim his lands with the help of a "Danish" fleet as the background to the plot.