Cuilén was an early King of Alba (Scotland).
He was a son of Illulb mac Custantín, King of Alba, after whom he is known by the patronymic mac Illuilb of Clann Áeda meic Cináeda, a branch of the Alpínid dynasty.
During the 10th century, the Alpínids rotated the kingship of Alba between two main dynastic branches. Dub mac Maíl Choluim, a member of a rival branch of the kindred, seems to have succeeded after Illulb's death in 962. Cuilén soon after challenged him but was defeated in 965. Dub was eventually expelled and slain in 966/967. Whether Cuilén was responsible for his death is uncertain.
Cuilén
Detail of inscriptions upon Sueno's Stone which may represent Dub's demise. The visible arch could represent a bridge, and the framed head under the arch may represent Dub, whose body was traditionally said to have been hidden beneath a bridge.
A hogback grave slab on display in Glasgow. Such monuments may be indicative of Scandinavian settlement in Perthshire and Fife. The aforesaid evidence of Scandinavian influence upon Cuilén's immediate family could indicate that his kindred was involved with such immigration.
Rhydderch ap Dyfnwal was an eminent tenth-century Cumbrian who slew Cuilén mac Illuilb, King of Alba in 971. Rhydderch was possibly a son of Dyfnwal ab Owain, King of Strathclyde, and could have ruled as King of Strathclyde. Rhydderch appears on record in about 971, when he is said to have killed Cuilén mac Illuilb, King of Alba, a man said to have abducted and raped Rhydderch's daughter. Following Cuilén's death, the Cumbrian Kingdom of Strathclyde endured an invasion by Cuilén's successor, Cináed mac Maíl Choluim, King of Alba. This Scottish attack could have been a retaliatory raid for Rhydderch's actions, and may have been undertaken in the context of restoring Scottish authority over the Cumbrian realm. If Rhydderch ever ruled as king it must have been before 973, when Dyfnwal's son, Máel Coluim, is accorded the title king.
The title of Dyfnwal ab Owain as it appears on folio 33v of Oxford Bodleian Library Rawlinson B 489 (the Annals of Ulster). Irish sources accord him the title rí Bretan ('King of the Britons'). It is unknown if Rhydderch was himself a king. Certainly, the Annals of Ulster accords Dyfnwal's son and successor, Máel Coluim, the title rí Bretan Tuaiscirt ('King of the Northern Britons').
