Yuhanna ibn Masawaih (circa 777–857), (Arabic: يوحنا بن ماسويه), also written Ibn Masawaih, Masawaiyh, and in Latin Janus Damascenus,[1] or Mesue, Masuya, Mesue Major, Msuya, and Mesuë the Elder was a Persian[2] or Assyrian East Syriac Christian physician[3][4] from the Academy of Gundishapur. According to The Canon of Medicine for Avicenna and 'Uyun al-Anba for the medieval Arabic historian Ibn Abi Usaybi'a, Masawaiyh's father was Assyrian and his mother was Slavic.[5]