Isa Kelemechi

Debate between Catholics (left) and Church of the East Christians (right) in the 13th century. Acre, Kingdom of Jerusalem circa 1290. ʿIsa Tarsah Kelemechi (, ) was a Church of the East astronomer and physician at the Yuan court of Kublai Khan's Mongol Empire in the 13th century.

Astrologer in China ʿIsa was named head of the Office of Western Astronomy established by Kublai Khan in 1263 to study Islamic astronomical observations. Kubilai would establish a Observatory for Islamic astronomy in 1271, directed by astronomer Jamal ad-Din Bukhari. ʿIsa also showed to Khubilai the Sword Verse of the Quran, raising the suspicion of the Mongols towards Muslims. The message, written in imperfect Latin, said:

The 1285 embassy would be followed in 1287 by that of Rabban bar Sauma.