Bishop Cyril S. Terlecki (died May 1607) was a religious and political figure and one of the initiators of the conclusion of the Union of Brest in 1596.
He came from a noble family, whose roots were in Peremyshlyanschyni. Members of this family held high ecclesiastical positions in the first half of the 15th century. In the 1560s, he was the archpriest of St. Dmitry in Pinsk. In 1572, the then Bishop of Turov-Pinsk, Brest, Andrew Rusin, died. In 1575, Terlecki, who at that time was a widower and could accept monastic tonsure, began fighting for the Turov-Pinsk Diocese and during the interregnum received a diploma in Turov-Pinsk diocese. Terlecki supported Prince Konstanty Wasyl Ostrogski, who had land holdings in Pinschyni. Becoming a bishop, Terlecki demanded rights and privileges of the clergy, collected documents from the historical past of his bishop, made a diocesan archives. Special attention is paid to strengthening the economic situation of the church. Built the Church of St. Ghost in Pinsk, cared for the poor. In 1585 the bishop of Lutsko Ostrozhsky, John-Borzobahatyy Krasenskyy, died. In May 1585, King Stefan Batory appointed Terlecki Lutsko-Ostrog bishop. In August 1589 Ecumenical Patriarch Jeremias II appointed Terlecki as Exarch – the first for a Ukrainian bishop.
- 1575 – 1585 – Turov-Pinsk Orthodox bishop
- 1585 – 1595 – Lutsk-Ostrog Orthodox bishop
- 1596 – 1607 – Lutsk-Ostrog Uniate Bishop
Decline of the Orthodox Church in the lands of the Commonwealth led Terlecki and other bishops to seek a rapprochement with the Catholic Church. In June 1590 the congress of bishops in Belha, Terlecki together with other bishops first raised the issue of the necessity of the Orthodox and Catholic churches. In 1594 at the Congress in the Zocalo, Terlecki instructed to negotiate the conclusion of a future union. In June 1595 members of the cathedral at Brest agreed texts of the appeals to the Polish King Sigismund III Vasa and Pope Clement VIII, and decided to send a delegation consisting of Terlecki and Ipatii Potii to Rome. Terlecki participated in the Cathedral of Brest in 1596, which was solemnly proclaimed the conclusion of Metropolis of Kiev´s church union and the Catholic Church. In 1598 received from King Sigismund III Vasa the title of archimandrite. Buried in Lutsk Cathedral.
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