 Complete the following phrase:  Helena Palaiologina ; 23 April 1442  1469 was the daughter and only child of Demetrios Palaiologos, Despot of Morea, a brother of the final Byzantine emperor Constantine XI Palaiologos. Her mother was Theodora Asanina of the Asen family, a family which had once ruled Bulgaria. Famous for her beauty, Sultan Mehmed II, who had 