History of Yuan
The "History of Yuan" (chapter 134) records that a certain Ai-sie (transliteration of either Joshua or Joseph) from the country of Fu lin (i.e. the Byzantine Empire), initially in the service of Güyük Khan, was well-versed in Western languages and had expertise in the fields of medicine and astronomy that convinced Kublai Khan to offer him a position as the director of medical and astronomical boards. Kublai Khan eventually honored him with the title of Prince of Fu lin (Chinese: 拂菻王; "Fú lǐn wáng"). His biography in the "History of Yuan" lists his children by their Chinese names, which are similar to the Christian names Elias ("Ye-li-ah"), Luke ("Lu-ko"), and Antony ("An-tun"), with a daughter named "A-na-si-sz".