Rabban Bar Sauma (fl. 1280-1288), Nestorian traveller and diplomatist, was born at Peking about the middle of the 13th century, of Uigur stock. While still young he started on a pilgrimage to Jerusalem, and travelling by way of Tangut, Khotan, Kashgar, Talas in the Syr Dania valley, Khorasan, Maragha and Mosul, arrived at Ani in Armenia. Warnings of the danger of the routes to southern Syria turned him from his purpose; and his friend and fellow-pilgrim, Rabban Marcos, becoming Nestorian patriarch (as Mar Yaballaha III.) in 1281, suggested Bar Sauma's name to Arghun Khan, sovereign of the Ilkhanate or Mongol-Persian realm, for a European embassy, then contemplated. The purpose of this was to conclude an anti-Moslem alliance, especially against the Mameluke power, with the chief states of Christendom. On this embassy Bar Sauma started in 1287, with Arghun's letters to the Byzantine emperor, the pope and the kings of France and England. In Constantinople he had audience of Andronicus II.; he gives an enthusiastic description of St Sophia. He next travelled to Rome, where he visited St Peter's, and had prolonged negotiations with the cardinals. The papacy being then vacant, a definite reply to his proposals was postponed, and Bar Sauma passed on to Paris, where he had audience of the king of France (Philip the Fair). In Gascony he apparently met the king of England (Edward I.) at a place which seems to be Bordeaux, but of which he speaks as the capital of Alanguitar (i.e. Angleterre). On returning to Rome, he was cordially received by the newly elected pontiff Nicolas IV., who gave him communion on Palm Sunday, 1288, allowed him to celebrate his own Eucharist in the capital of Latin Christendom, commissioned him to visit the Christians of the East, and entrusted to him the tiara which he presented to Mar Yaballaha. His narrative is of unique interest as giving a picture of medieval Europe at the close of the Crusading period, painted by a keenly intelligent, broadminded and statesmanlike observer.
See J. B. Chabot's translation and edition of the Histoire du Patriarche Mar Jabalaha III. et du moine Rabban Cauma (from the Syriac) in Revue de l'Orient latin, 18 93, pp. 566-610; 1894, PP. 731 43, 2 35-3 00; O. Raynaldus, Annales Ecclesiastici (continuation of Baronius), A. D. 1288, §§, xxxv.-xxxvi.;1289, § lxi.; L. Wadding, Annales Minorum, v. 169, 196, 170-173; C. R. Beazley, Dawn of Modern Geography, ii. 1 5, 352; iii. 12, 189-190, 539-541.
