An interesting interpretation given by Alex Woolf in Pictland to Alba: 789-1070, based on both the Annals of Ulster (AU) and the Annals of Tigernach (AT), is that, given two seemingly independent sources (the annals), Lulach actually preceded Macbeth in death.
AU 1058.2 Lulach son of Gilla Comgáin, high-king of Alba, was killed in battle...
AU 1058.6 Macbethad soin of Findláech, high-king of Alba, was killed in battle...
AT 1058.1 Lulach, king of Alba, was slain...
AT 1058.65 Macbethad son of Findláech, high-king of Scotland, as slain...
Woolf, p. 264: "More curious is the fact that AU and AT, at this point seemingly independent witnesses, both place3 Macbethad's death after Lulach whereas all the kings-lists grant Lulach a reign of several months following Macbethad. Had this apparent mis-ordering occurred in a single chronicle we might have dismissed it as a slip but the coincidence of both making the same slip would seem odd. The simplest solution to the proboem is to presume tat Macbethad had demitted the kingship to Lulach, willingly or under duress, but was actually still alive when his successor was slain...
"If Macbethad had in fact demitted the kingship this could still lave him alive to be killed by Mael Coluim in August 1058."
Obviously, a fuller quoting of Woolf might give a better view of things, which would include Marianus' chronicle for more precise dating. And, I must admit that this is not an area of expertise in which I operate. So, given AU and AT, might a reevaluation of the dating and order of these two kings be in order?
Thoughts?