Uuen son of Onuist (Old Irish: Eogán mac Óengusa; died 839), commonly referred to by the hypocoristic Eóganán, was king of the Picts between A.D. 837–839.
The sole notice of Uuen in the Irish annals is the report of his death, together with his brother Bran and "Áed mac Boanta, and others almost innumerable" in a battle of 839 fought by the men of Fortriu against Vikings in 839.
[1] This defeat appears to have ended the century-long domination of Pictland by the descendants of Onuist I [son of] Wrguist (in Gaelic: Óengus I mac Fergusa).
[3] Along with his uncle Caustantín, Uuen appears to have been a patron of the Northumbrian monasteries as he is named in the Liber Vitae Dunelmensis, which contains a list of those for whom prayers were said, dating from around 840.
[4] Uuen, his father, his uncle and his cousin Domnall appear in the Duan Albanach, a praise poem from the reign of Máel Coluim (III) mac Donnchada listing Máel Coluim's predecessors as kings of Scots, of Alba and of Dál Riata from Fergus Mór and his brothers onwards.