A good book on the unusual emperor Rudolf II. is "Der Alchimist von Prag" by J. Dauxois
Some people say that he was just crazy, but actually he was a very interesting figure of his time, even when different from the others of his family. Even concerning his confession etc he was some kind of outsider. He hated the spanish inquisition. Very interested in studied of alchemy, astrology etc etc, his political descisions and talents were very discussed. He made his palace in Prague to a famous place for scienstis and alchimists from all over Europe. Later on Matthias took the chance and took away his crown, as he saw that he wasn´s able to rule anymore! Yes, Rudolf didn´t want to marry, that´s true. There were four brides for him, but he could never decide himself. But he had children by a mistress. On of them Don Cesar was very brutal, he rapped a lady, killed her, hacked her into pieces and then divided them in the whole room. Then he committed suicide. There were strange genes in the family of Rudolf. Even Rudold himself made strange things, he shall have threatened one of his people with a dagger and other things like that. The book on him was very interesting!