I'm reading Pavane by Keith Roberts, which is an alternate history where the Catholics assissinated Elizabeth I, thereby paving the way for the Spanish Armada to sack England and set up a Catholic state, keeping all of Europe in the Dark Ages well into the 20th Century.
It's part of a
group book read on this
Science Fiction message board that I am one of the Admins for. We do the group reads every couple months.