when was the name constantinople changed to istanbul
Names of Istanbul Names other than استانبول (İstanbul) had become obsolete in the Turkish language during the late Ottoman/early republican periods. However, Constantinople was still used when writing the city's name in Latin script. In 1928, the Turkish alphabet was changed from Arabic script to Latin script. After that, Turkey started to urge other countries to use Turkish names for Turkish cities, instead of other transliterations to Latin script that had been used in the Ottoman times.[19] Letters or packages sent to "Constantinople" instead of "Istanbul" were no longer delivered by Turkey's PTT, which contributed to the eventual worldwide adoption of the new name.[citation needed]
Constantinople From the mid-5th century to the early 13th century, Constantinople was the largest and wealthiest city in Europe[6] and it was instrumental in the advancement of Christianity during Roman and Byzantine times as the home of the Ecumenical Patriarch of Constantinople and as the guardian of Christendom's holiest relics such as the Crown of Thorns and the True Cross. After the final loss of its provinces in the early 15th century, the Byzantine Empire was reduced to just Constantinople and its environs, along with Morea in Greece, and the city eventually fell to the Ottomans after a month-long siege in 1453.