This is the Knotel plate I mentioned, clearly related to the first image, with all the problems Tacitus has made clear. http://upload.wikimedia.org/wikipedia/commons/d/dd/Kn%C3%B6tel_III,_36.jpg My guess is that it was inspired by this cap, which it resembles; http://rusmilhist.blogspot.co.uk/2012/1...