Leonard of Chios (Greek: Λεονάρδος ο Χίος; Italian: Leonardo di Chio), also called Leonardo Giustiniani,[1] was a Greek scholar of the Dominican Order and Latin Archbishop of Mytilene, best known for his eye-witness account of the Fall of Constantinople in 1453, which is one of the main sources for the event.
[3] In 1452, Cardinal Isidore of Kiev stopped at Lesbos on his way to Constantinople to conduct negotiations for a union between the Catholic and Greek Orthodox churches.
[5] Leonard soon managed to find passage to Chios, from where on 16 August he wrote to Pope Nicholas V a detailed account of the fall of Constantinople in a letter.
Written in Latin, Leonard's letter "describes the conquest in a fashion hostile to the Byzantines and Venetians but favorable to the Genoese".
[3][7] His best-known writings is the letter mentioned above and an apologetical tract in answer to the humanist Gian Francesco Poggio Bracciolini.