Originally posted by Greyhawk1
I dont know whether this has been mentioned before but the Romans have a city in their city names list called Byzantium which is confusing considering I'm playing the Byzantines in my current game 
This is correct.
The original name of the place was Byzantium, going back to Classic Greek times (meaning it could legitimately be on their city list, too).
Later in Roman times it was a part of the Roman Empire. After a lengthy period of civil wars between various generals who wanted to be emperor (some of whom made it, for a while), a guy named Diocletian came out on top. He reformed the Empire to divide the administration into Eastern & Western halves, each ruled by an "Augustus" and assisted by a "Caesar" (who each got 1/4 of the Empire to play with). Every 20 years, the Augusti were supposed to retire, the Caesars advance to Augusti and appoint new Caesars from the next generation. The idea was to coopt potential rebels into the administration and provide an orderly succession.
A generation later it broke down, and Contantine ("the Great") came out after another round of civil wars as sole Emperor. He rebuilt Byzantium into a capital for the reunited Empire and renamed it "New Rome" ("Nova Roma"), but everybody else called it Constantinople ("Contantinopolis" = "Constantine's City") and that name stuck.
The Eastern & Western Empires split & reunited a couple more times before splitting for good. The Western half was carved up into Kingdoms by various Germanic tribes and finally put out of its misery in 476 AD. The Eastern half lived on, but on a mostly downward trend, until the Ottoman Turks put it out of its misery in 1456 AD. During that time, since the heart of the Empire was now in Greek-speaking territory, the official language evolved from Latin to Greek. A lot of bad blood arose between the Kingdoms (and Pope) of Western Europe and the Emperors (and Patriarchs) of Constantinople, over religion & politics (and the combination thereof). In modern times, Western European classical scholars wishing to de-emphasis the Roman heritage of that Empire centered on Constantinople took to calling it the "Byzantine" Empire, after the original Greek name of Constantinople. Meanwhile, after the Ottoman Empire fell, the Turks renamed the place (yet again) to "Istanbul".
In summary, Byzantium => Nova Roma => Constantinople => Istanbul. Same spot on the map.
