The Byzantines never called their empire Byzantine; a German historian did in 1555
For a thousand years the people of the eastern empire called their state the Empire of the Romans. The label Byzantium, taken from the old Greek city beneath Constantinople, was applied to the whole state by historian Hieronymus Wolf in 1555, a century after the empire had vanished. The name stuck anyway.
The original Byzantion was a Greek colony planted by settlers from Megara, near Athens, in the 7th century BC. Legend names its founder as Byzas, and the name may come from a Thracian personal name meaning he-goat, though its real origin is unknown. Herodotus implies a founding date of 667 BC, seventeen years after neighbouring Chalcedon; Eusebius, writing centuries later, gives a different date. Constantine the Great sided with Herodotus and celebrated the city's thousandth anniversary in 333 and 334.
Location made the city rich and fought over. It controlled the only entrance to the Black Sea, so it thrived on trade. Darius I of Persia took it around 513 BC, Sparta seized it in 411 BC to choke Athens' grain supply, and Athens recovered it in 408 BC. Backing the losing side in a Roman civil war brought a siege and heavy damage in AD 196, but Septimius Severus rebuilt it. Almost surrounded by water, it caught Constantine's eye, and in 330 he refounded it as Nova Roma, soon known as Constantinople.
A local legend may explain an enduring symbol. In 340 BC, when Philip of Macedon attempted a surprise night attack, a bright light in the sky reportedly exposed his troops. Later retellings call it a meteor or the moon, but the original accounts mention only a light. The grateful citizens honoured Hecate, the light-bearing goddess, whose emblems were the crescent and star, and coins from the 1st century BC show a crescent with an eight-rayed star.
The city's name also travelled into everyday language. From the 9th century, Byzantine gold coins were called besants or bezants, a word English borrowed in the 12th century. After the Ottoman conquest on May 29, 1453, the city became Istanbul, from a Greek phrase meaning to the city, though the name was not made official until 1930. Ancient Byzantium's site lies at Sarayburnu.
Source: Byzantium
