It is unknown when Dyfnwal's reign came to an end. There is reason to suspect that a certain Rhydderch ap Dyfnwal was a son of his, and that this man ruled when he assassinated the reigning King of Alba in 971. Certainly by 973, Máel Coluim was associated with the kingship, as both he and his father are recorded to have participated in a remarkable meeting of kings assembled by Edgar, King of the English. The context of this assembly is not entirely clear. It could have concerned the stability of the border between the English realm and that of the Scots and Cumbrians. It could have also focused upon lurking threat of Vikings based in Dublin and the Isles.