Giovanni da Pian del Carpine
For his history of the Mongols Hayton names an "Estoires des Tartars" ("History of the Tartars") as his source for the time until the reign of Möngke Khan (1250s), while for more recent events, he relies on the accounts by his great-uncle, king Hethum I, and on his own experiences. He is also informed by western sources on the history of the Crusades, and most likely draws on the travelogues of Giovanni da Pian del Carpine and Marco Polo.