Thomas Palaiologos, Despot of Morea (born 1409)

Thomas Palaiologos was Despot of the Morea from 1428 until the fall of the despotate in 1460, although he continued to claim the title until his death five years later. He was the younger brother of Constantine XI Palaiologos, the final Byzantine emperor. Thomas was appointed as Despot of the Morea by his oldest brother, Emperor John VIII Palaiologos, in 1428, joining his two brothers and other despots Theodore and Constantine, already governing the Morea. Though Theodore proved reluctant to cooperate with his brothers, Thomas and Constantine successfully worked to strengthen the despotate and expand its borders. In 1432, Thomas brought the remaining territories of the Latin Principality of Achaea, established during the Fourth Crusade more than two hundred years earlier, into Byzantine hands by marrying Catherine Zaccaria, heiress to the principality.

The Despotate of the Morea or Despotate of Mystras was a province of the Byzantine Empire which existed between the mid-14th and mid-15th centuries. Its territory varied in size during its existence but eventually grew to include almost all the southern Greek peninsula now known as the Peloponnese, which was known as the Morea during the medieval and early modern periods. The territory was usually ruled by one or more sons or brothers of the current Byzantine emperor, who were given the title of despotes. Its capital was the fortified city of Mystras, near ancient Sparta, which became an important centre of the Palaiologan Renaissance.