George Sphrantzes, also Phrantzes or Phrantza (Greek: Γεώργιος Σφραντζῆς or Φραντζῆς; 30 August 1401 – c. 1478), was a late Byzantine Greek historian and Imperial courtier. He was an attendant to Emperor Manuel II Palaiologos, protovestiarites ("Lord of the Imperial Wardrobe") under John VIII Palaiologos, and a close confidant to Constantine XI Palaiologos, the last Byzantine emperor. He was an eyewitness of the Fall of Constantinople in 1453, made a slave by the victorious Ottomans, but ransomed shortly afterwards. Sphrantzes served the surviving members of the Palaiologian family for the next several years until taking monastic vows in 1472. It was while a monk he wrote his history, which ends with the notice of Sultan Mehmed II's attempt to capture Naupaktos, which he dates to the summer of 1477; Sphrantzes is assumed to have died not long after that event.