The new Turkish movie Fetih 1453 (Conquest 1453) is about the conquest of Constantinople by Ottoman sultan Mehmed II, which brought about the death of the last Byzantine emperor, Constantine XI Palaiologos. Here is the official trailer, with English subtitles. (Warning: includes battle scenes.) It looks very Lord of the Rings to me:
Visit Royalty.nu for books about Mehmed II and Constantinople (Istanbul). You can read about Constantine XI Palaiologos in The Immortal Emperor by Donald M. Nichol, and here are more books about the Byzantine Empire and its rulers.