400. That’s an error.

Google cannot redirect you to http://worldcat.org/search?q=Foedera, conventiones, literae et cujuscunque generis acta publica inter reges Angliae et alios quosvis imperatores, reges, pontifices ... ab ineunte saeculo duodecimo, viz. ab anno 1101 ad nostra usque tempora, habita aut tractata ... because the request was invalid.

This might be because the link was created a long time ago. Try your search again on Google. That’s all we know.