The Itinerary of Benjamin of Tudela

"[...]kinsmen the Seljuks they settled in Asia Minor, and embraced the Mohammedan faith, an example which many Mongols followed. The converts proved trusty warriors to fight the cause of Islam, which gradually attained the zenith of success. On May 29, 1453, Constantinople was captured by the Turks, and an end was made of the Byzantine Empire. Eastern Europe was subsequently overrun by them, and it was not until John Sobieski defeated the Turks under the walls of Vienna in 1683 that their victorious career was checked.[...]".