Excerpts from Books and Wikipedia
Istanbul (new name for Constantinople) becomes the capital of the Ottoman Empire. "Yet while Mehmed assembled 80,000 Turks and Serbs and a powerful fleet to attack Constantinople, Byzantine Emperor Constantine XI could muster only 7,000 soldiers to defend it. . . . The last Byzantine emperor died sword in hand." [Furtado: 1001 Days] "End of the Byzantine Empire (or Eastern Roman Empire to some); Constantinople becomes capital of Ottoman Empire." [Wikipedia: Timeline of Middle Ages]