TIMOTEO I, NESTORIAN PATRIARCH. – Born in 727 or 728 at Hazzà near Arbela, he died in 823. A monk in the monastery of St. George, he later became bishop of Bejt Bagaš and, in 779, patriarch.
After two years of struggle to have his office recognized by all, he governed his Church—which at that time reached its greatest expansion—with wisdom and firmness, in relative peace, for more than 40 years. He founded six new ecclesiastical provinces; he sent missionaries, generally monks, to the Caspian Sea, Transoxania, as far as distant Tibet, and southern Arabia; he improved the training of the clergy by founding schools and took great care in the selection of bishops. With the court of the 'Abbāsid caliphs in Baghdad, where he had powerful supporters, he always managed to maintain good relations, and before the caliph al-Mahdi he defended the Christian religion in a public disputation.
Among his writings, first of all, his numerous and highly interesting letters—more than 200—should be noted, together with a series of canonical decisions and his apology for Christianity before the caliph al-Mahdi. His Christological doctrine is essentially that common to the Nestorians. He acknowledged the necessity of Grace; his conception of the Eucharist seems correct; he admitted the validity of Baptism administered by Catholic or Monophysite priests; he regarded the five patriarchs as equal among themselves, with a certain pre-eminence belonging to the patriarch of Seleucia-Ctesiphon.