when did constantinople become istanbul

Constantinople officially became Istanbul in 1930, when the Republic of Turkey adopted “Istanbul” as the city’s official name and asked other countries and postal services to do the same.

Quick Scoop

• The city was founded as Byzantium in antiquity, renamed Constantinople by Emperor Constantine around 330 CE, and kept that name through the Byzantine and much of the Ottoman era.

• After the Ottoman conquest in 1453, the city was often called “Kostantiniyye” in official Ottoman documents, while “Istanbul” was widely used in everyday speech, likely evolving from the Greek phrase “eis tin polin” (“to the city”).

• The turning point came in 1930, when the new Turkish Republic standardized place names and made “Istanbul” the formal, internationally used name, replacing “Constantinople” in official and postal usage.

In short: people had been saying “Istanbul” for centuries, but it only officially replaced “Constantinople” in 1930.

Information gathered from public forums or data available on the internet and portrayed here.