A fortnight ago I experimented by linking to a picture that I saw on Twitter and really liked. The response from readers was favourable, and while I don't see enough material on Twitter for this to be a regular feature, I thought I'd try again this week. Erik Kwakkel (@erik_kwakkel) put up a picture he'd found in the margins of a manuscript from the National Archives. It's small, but clearly shows murdered English Archbishop Thomas Beckett being struck in the head by a sword. There are plenty of interesting illustrations like this in the margins of medieval documents, and this one is darkly creative.