The History of the Decline and Fall of the Roman Empire, by Edward Gibbon

Chapter LXIV: Moguls, Ottoman Turks

Conquests Of Zingis Khan And The Moguls From China To Poland.—Escape Of Constantinople And The Greeks.—Origin Of The Ottoman Turks In Bithynia.—Reigns And Victories Of Othman, Orchan, Amurath The First, And Bajazet The First.—Foundation And Progress Of The Turkish Monarchy In Asia And Europe.—Danger Of Constantinople And The Greek Empire.