[Junior]

It wasn't Istanbul at the time -- it was Constantinople.

[PatrickHenry]

There is great potential for name-confusion here. Originally the city was Byzantium, a Greek outpost. When the Roman emperor Constantine moved his eastern capitol there (in the early 300s, AD), it was re-named Constantinople. It became the center of the so-called Eastern Roman empire, and after the fall of Rome it was often called the Byzantine empire (a reversion to the original Greek name). After the Turks took over, per the article above, it became Istanbul. (If present and still-secret plans are successful, it may be called "George W. Bush City.")

[Billthedrill]

Actually, the pronunciation "Istanbul" is nothing but a Turkish corruption of the Greek "Constantinople" - they didn't think they were even changing the name when they took the town. And for good reason - it was, at the time, the most impressive city in the world. (Lest we get too amused by this, the way we pronounce "Constantinople" in English isn't right either).