Mission to Rostov
Theodore's episcopate belongs to the first generation of the Church in Rus', established after the conversion of Great Prince Vladimir. The Rostov diocese was founded at the end of the tenth century, dated variously between 990 and 992, and Theodore, a Greek monastic, received appointment as its inaugural bishop. By one account he set about building a wooden church dedicated to the Dormition of the Virgin Mary. As the first bishop of Rostov he confronted a region where Christianity had not yet taken root, and the sources present his work there as missionary in character rather than the administration of an already-Christian flock.
The sources record that the pagan inhabitants of Rostov met the hierarch with hostility, offering him many insults and on one occasion driving him from the city. This opposition led him to withdraw to Suzdal, a transfer that gives him his double title as bishop of Rostov and Suzdal.