John VIII Palaiologos

John VIII Palaiologos or Palaeologus (Greek: Ίωάννης Η' Παλαιολόγος, Iōannēs VIII Palaiologos, 18 December 1392 – 31 October 1448), was the penultimate reigning Byzantine Emperor, ruling from 1425 to 1448. John VIII Palaiologos was the eldest son of Manuel II Palaiologos and Helena Dragaš, the daughter of the Serbian prince Constantine Dragaš. He was associated as co-emperor with his father before 1416 and became sole emperor in 1425. In June 1422, John VIII Palaiologos supervised the defense of Constantinople during a siege by Murad II, but had to accept the loss of Thessalonica which his brother Andronikos had given to Venice in 1423. To secure protection against the Ottomans, he visited Pope Eugene IV and consented to the union of...