Cath. of the Ch. of E. Timotheos was born in the village of Ḥazza (near Arbela in Iraq). His education was supported by his uncle Gewargis, the bp. of Beth Begash. In Bashosh and Marga he studied with the famed scholar Abraham bar Dashandad . Abraham was renowned as a scholar of the Bible and of Aristotle . He was also an effective teacher of techniques of translation from Greek into Syriac. Timotheos succeeded his uncle as bp. of Beth Bgash.
In 779, the Cath. Ḥenanishoʿ II was poisoned. At the convocation of bishops in 780, Timotheos was elevated to the patriarchate, a position he would hold through the rule of five caliphs. Timotheos worked to improve the status of Christians in the Caliphate and beyond through a variety of initiatives.
First, he worked to improve the moral and educational level of both clergy and laity. He encouraged scholarship, including the development of linguistic skills. He both translated (Aristotle’s Topics) and encouraged the translation work of others, assuring that a large number of texts were translated from Greek into Syriac and Arabic. More than two hundred letters were known, about 59 of which survive. Timotheos was also the author of ‘The Ordinances of Ecclesiastical Judgments and of Inheritance’. This still unpublished tome sought to bring reasoned order to the churches. Timotheos’s contributions to biblical studies, hermeneutics, and Bible translation were significant. He even obtained a copy of Origen’s Hexapla in order to have access, for himself and his translators, to the best possible biblical text. Timotheos also wrote, according to ʿAbdishoʿ bar Brikha , a commentary on a text of Gregory of Nazianzus .
Timotheos also established the juridical structures of the E.-Syr. Church including the development of the Synodicon Orientale, a collection of the decisions of the councils of the E.-Syr. Church. Most importantly, he improved understanding between Christians and Muslims. His dialogue with Caliph al-Mahdī (775–85) is preserved in both Syriac and Arabic. Beyond the formal discussions, his diplomatic skills facilitated the development of the E.-Syr. church in the Caliphate and throughout Asia.
The organization and spread of Christianity in Asia and the Middle-East consumed a lot of Timotheos’s energy. He organized and/or revitalized organization of the churches in areas as diverse as China, Tibet, Yemen, India, and Central Asia. He encouraged the production of theological literature in the indigenous languages and the development of indigenous non-Syrian leadership of churches. While Christians had been establishing communities along the trade routes of Asia for centuries, Timotheos provided structure and intellectual renewal for the ongoing traditions.