Byzantium was a city now known as Istanbul, pronounced 'biz-ANT-i-erm (or oom'), IPA: /bɪz ˈænt ɪ ə (or u)m/, or, less commonly, 'buy-ZANT-i-um (or oom), /baɪ ˈzænt ɪ ə (or u)m/. Between these two names, it was called Constantinople. The adjective meaning 'to do with Byzantium' is Byzantine.
- The original city was a Greek colony. The legends state that it was founded by king Byzas of Megara around 670 BCE. Its Greek name, Βυζάντιον (byzantion) is derived from his name (Βὐζας). Another speculation is that it is derived from the Indo-European *bhugo 'stag'.
- Its site, on the southern tip of the northern side of the Hellespont at the gateway to the Black Sea, with good anchorage in the Golden Horn, made it ideal for the Emperor Constantine the Great to choose for the new capital of the Eastern Roman Empire.
- This was at first sometimes called Νέα Ῥώμη, 'Nea Rōmē' as it was an alternative capital for the Roman Empire, but this was rarely a title formally used for the city. The city had been briefly called Augusta Antonina in honour of the son Caracalla (or Marcus Aurelius Severus Antoninus Augustus) (188–217) of Septimius Severus (146–211), who had razed it and subsequently rebuilt it.
- Building of a new city on the old site was begun in 326 CE, and Constantinople (from the Greek Κωνσταντινούπολις 'Constantinoupolis', meaning 'city of Constantine') was consecrated in 330.
- It was known by the Greeks as Stanbulin or Bulin. The former survives into the modern aphetic Stamboul, which became used in anglophone countries for the walled city that survived of Constantinople within Turkish Istanbul - which western sources preferred to call Constantinople. Graham Greene wrote a novel (an 'entertainment') called Stamboul Train (1932). There was, by coiuncidence, a film in the same year called Stamboul. This was baseds on Claude Farrère's French novel L'homme qui assasina (1906).
- It was the capital of the Empire, and home of the Eastern Emperors, until it fell.
- In 1453, the Ottoman Sultan, Mehmed or Mehmet II ('Mehmed the Conqueror') captured Constantinople. (He was aged 21 at the time, and deserves much credit for his strategy and determination.) The Fall of Constantinople was marked by looting of plunder, rape and enslavement of the able-bodied Christian defenders and slaughter of many of the rest. The city was renamed Istanbul, a spoken Turkish corruption of the Greek εἰς τὴν πόλιν 'eis tin polin' 'in[to] the city'. Istanbul served as the capital of the Ottoman Empire until 1923, when, with the foundation of the Republic of Turkey, the capital was moved to Ankara. Istanbul is still the name of the city on the Bosporus.
- Two poems by W.B. Yeats, 'Sailing to Byzantium' (1926) and 'Byzantium' (1930), use Byzantium as a symbol of riches, and of spirituality and religion. The sacred city is a home of art and seriousness.