The early 11th century Chronicle of the Kings of Alba (CKA), in a passage referring to the reign of King Cuilén mac Iduilb (r. 966-71), says "Cellach filius Ferdalaig reg[navit]", i.e.
In the early 11th-century Chronicle of the Kings of Alba, when referring to King Cuilén mac Iduilb's rule (966-71), it is recorded as "Cellach filius Ferdalaig regnavit," suggesting that