The term ONE CONSTANTINOPLE RULER refers to the OTTOMAN Empire, which was a powerful state that existed from 1299 to 1922. The ruler of this empire was known as the OTTOMAN Sultan, and the word 'OTTOMAN' is an English transliteration of the Turkish word 'Osmanlı', which was the name of the dynasty that ruled the empire. The OTTOMAN Empire was centered in Constantinople (now Istanbul), and its rulers were responsible for the expansion of the empire into much of the Middle East, North Africa, and parts of Europe.