Constantine XI Palaiologos
George Palaiologos Kantakouzenos was likely the son of Theodore Palaiologos Kantakouzenos. Among his siblings were the Despotess of Serbia Irene Kantakouzene, the Empress of Trebizond Helena, and the unnamed wife of King George VIII of Georgia. He was also a cousin of the last two Byzantine emperors, John VIII Palaiologos and Constantine XI Palaiologos.