If Máel Coluim succeeded Dyfnwal, it could mean that Rhydderch—if he was indeed Máel Coluim's brother—was either dead or unable to reign as king. Whilst it is possible that the sons of Dyfnwal maimed by the English in 945 were still alive in the 970s, the horrific injuries endured by these men would have meant that they were deemed unfit to rule. Notwithstanding the uncertainties surrounding his accession, Máel Coluim's reign was evidently unremarkable. Certainly, no source records Scottish-Cumbrian political relations at about the inception of Máel Coluim's reign, although the fact that Dyfnwal left for Rome could be evidence that the latter did not regard the realm or dynasty to be threatened during his absence.