Looking at Merlin's post on the Anglo-Saxon and Viking victories according to the Anglo-Saxon Chronicle - which is fascinating, by the way - I was reminded of the difficulties of dating events precisely. He gives 917 as the date when a battle was fought at Maldon. I seem to remember this date being cited in a secondary source somewhere, but when I quickly looked in the ASC to check it myself (in Garmonsway's edition) it says this occured in 920 - though this may be a copying error for 919. But this copying error in itself shows the difficulty in dating things accurately, in addition to the times when we can show that at least one of the chroniclers has assigned the wrong date to a certain event. I'd be interested to hear people's thoughts on this aspect of the ASC - and more examples of confused chroniclers!