Tale of three cities, watched this a couple of weeks ago on the Smithsonian channel of it may have been PBS America channel but have found it online, find it fantastic viewing. It tells of it's brutal past & changing religions from it's formation to it's present day secular(mainly) Istanbul. The video quality isn't good though, this is the first of three, if anyone 's interested.
I have Byzantium in my pile of unwatched DVDs. Oh, hang on... it's the erotic vampire movie with Gemma Arterton that's in my pile. Damn.
There's a documentary from the mid90s which is free on Youtube called Byzantium which is amazing to watch. A guy called John Romer presents it. He has a passion for the city and shows some amazing historical locations. I'd also recommend a book called Byzantium: The Last Great Siege 1453 by Roger Crowley. Its one that you can read numerous times and still feel the tension and fear of those holding on to defend it.