<prompt> Translate the following text to EnglishIstanbul ilikuwa makao makuu ya sultans wa Ottoman, watawala wa milki ya Kiislamu ya miaka 500 ambayo ilienea kutoka Bahari Nyeusi na Balkan hadi Arabia na Algeria.  <response>: As Istanbul it was the seat of the Ottoman sultans, rulers of a 500-year Islamic empire that stretched from the Black Sea and the Balkans to Arabia and Algeria. 