Istanbul is widely recognized as the name of Turkey's most well known city, but it was not always this way, and even today some confusion over its proper name still exists. The confusion is rooted in the various names the city assumed under the Ottomans in the centuries after their conquest of the city in 1453. Although the Ottomans did not purposely change the city's name, they opted to make "Constantinople" into a more Turkish style name "Konstantiniye" (which loosely translates as "of Constantine"), however variations on Konstantiniye soon cropped up.

"Stanbulin," (Greek for "to the city") once commonly found on road signs directing travelers to the capital, was punned by devout Turks into Islambol, where "Islam abounds." The names Islambol and Konstantiniye were used interchangeably in Ottoman documents up until the empire's demise in 1923. Westerners continued to refer to the city as Constantinople well into the 20th century. In the 19th century, however, the city's large foreign expatriate community took to calling the old city Stamboul. Western accounts of the old city during this period make regular references to the name.

Many times the Germans refer to Istanbul as 'Konstantinopel', the French and the British as 'Constantinople' and the Italians as 'Constantinopoli'. Although the official name of the city has, ever since the establishment of the Republic, been 'Istanbul' and great sensitivity shown on this subject, Europe resists the adoption of the name 'Istanbul'.