The term 'Byzantine or Ottoman' refers to two different empires that existed in the past. The Byzantine EMPIRE was a major power in the Eastern Mediterranean from the 4th century until its fall in 1453. It was centered in Constantinople, which is now Istanbul, Turkey. The Ottoman EMPIRE was a powerful state that lasted from 1299 to 1922 and was centered in what is now modern-day Turkey. Both empires had a significant impact on the region and the world.