<P> Stamboul or Stambul is a variant form of İstanbul . Greek for' the town' . Like Istanbul itself, forms without the initial i - are attested from early on in the Middle Ages, first in Arabic sources of the 10th century and Armenian ones of the 12th . Some early sources also attest to an even shorter form Bulin, based on the Greek word Poli (n) alone without the preceding article . (This latter form lives on in modern Armenian .) The word - initial i - arose in the Turkish name as an epenthetic vowel to break up the St - consonant cluster, prohibited in Turkish phonotactics . </P> <P> Stamboul was used in Western languages as an equivalent of İstanbul, until the time it was replaced by the official new usage of the Turkish form in the 1930s . In the 19th and early 20th centuries, Western European and American sources often used Constantinople to refer to the metropolis as a whole, but Stamboul to refer to the central parts located on the historic peninsula, i.e. Byzantine - era Constantinople inside the walls . </P> <P> Islambol (اسلامبول, Full of Islam) or Islambul (find Islam) or Islam (b) ol (old Turkic: be Islam), both in Turkish Language, were folk - etymological adaptations of Istanbul created after the Ottoman conquest of 1453 to express the city's new role as the capital of the Islamic Ottoman Empire . It is first attested shortly after the conquest, and its invention was ascribed by some contemporary writers to Sultan Mehmed II himself . Some Ottoman sources of the 17th century, most notably Evliya Çelebi, describe it as the common Turkish name of the time . Between the late 17th and late 18th centuries, it was also in official use . The first use of the word "Islambol" on coinage took place in 1703 (1115AH) during the reign of Sultan Ahmed III . The term Kostantiniyye still appeared, however, into the 20th century . </P> <P> Ottomans and foreign contemporaries, especially in diplomatic correspondence, referred to the Ottoman imperial government with particular honorifics . Among them are the following: </P>

When and why was the name of constantinople changed to istanbul