 The city by 1453 held less than a tenth of its former population.The city, known alternatively in Ottoman Turkish as "Ḳosṭanṭīnīye" ( after the Arabic form ) or Istanbul (while its Christian minorities continued to name it Constantinople, as did people writing in French, English, and other western languages), was the capital of the Ottoman Empire from its conquest in 1453 until the empire's collapse in 1922.Deriving the name of Istanbul from Constantinople
Contrary to another theory that the name Istanbul is derived from "εις την Πόλη" Greek for "to The City" pronounced "is-tin-poli", which does make logic, theory described next seems more plausible.