"Egbert may have contested the succession, but Offa successfully intervened in the ensuing power struggle on the side of Beorhtric." This sentence bugs me: if Egbert's contestation is uncertain (as the may suggests), how can we claim that there was a power struggle in which Offa had to intervene? Stenton states as a plain fact that Egbert and Beorhtric fought for the throne in 786 and that the latter won with Offa's help, but on the other hand Yorke, Kirby and the ODNB do not mention any part Egbert may have played in Cynewulf's succession. Also, according to Yorke, it is not certain that Beorhtric rose to power with Offa's help, she suggests he may have come under his influence later on.