Islambol is just a myth about where the name came from but researches show that "including the professors in my school" say that name of istanbul came from Eis tin poli,which means to the city in greek.the galata quarter,which is right at the north of the historic peninsula has always been the largest residential area specially for the greek inhabitants of the city because the historic peninsula was reserved for the sultan. Thats why the old istanbul was a passage way "to the city" which turned into istanbul in hundreds of years.Also there is no documents about the city being called islambol throughout the history.