In 1302, the Nestorian Catholicos Mar Yaballaha III, who as a young man had accompanied the older Rabban Bar Sauma from Khanbaliq (Beijing), sent a profession of faith to the Pope. He thereby formalized his conversion to Roman Catholicism, though a 1304 letter from him to the pope indicated that his move had been strongly opposed by the local Nestorian clergy.Luisetto, p.99-100
