[dc_denizen]

Istanbul (Constantinople) is a 2000 year old city; for hundreds of years, it was the largest and most developed city in the western world; in fact arguably it was the heart of the western world after the fall of Rome until around 800 a.d. It was a Greek city and the heart of the Greek world for much of its history, and only recently (1492 a.d.) was conquered by Muslims Turks.

Not sure I would classify is as a "developing" city, it's always been extremely important no matter who (Greeks, Romans, Byzantines, Turks) had control of it. If it was less prominent for the past 100 years or so, this was very anomalous.