I don't know if it's what you're looking for, but Stephen Fry's "Incomplete and Utter history of Classical Music" is a brilliant book. Does exactly what it says on the tin.

If you're looking for a good guide to Rome, Amanda Claridge's Archaeological Guide to Rome is excellent, and includes Byzantine churches as well as the ancient monuments. I'd also second the DK guide rec above - they're gorgeous books.

Have fun!

[edited to put link in!]