First Orthodox church in Siemiatycze The Orthodox church in Siemiatycze existed in the first half of the 15th century and may have been founded by the owner of Siemiatycze, Olechno Kmita Sudymontowicz, along with his wife, Fedora. However, the founding document of Olechno Kmita Sudymontowicz from 1431 is considered by many scholars to be a forgery. In subsequent centuries, the church's location on the outskirts, contrary to the town's development trends, was linked to the expansionist activities of the Catholic church following the
Council of Trent. The Siemiatycze church became a significant pilgrimage center, especially on the patronal feast of the Holy Trinity. However, after a new church was opened in the town in 1638, the main celebrations began to take place there. Seven years later, the owner of Siemiatycze, Michał Sapieha, announced plans to build a new church in place of the existing one due to its poor technical condition, but he did not fulfill his promises. In the visitation protocol conducted in 1774 by Father Antoni Karczewski, it was recorded that the building required extensive repairs. Fifteen years later, records from the consistory of the
Eparchy of Chełm–Belz noted that 2,511 people attended the church in Siemiatycze, including 458 residents of the town; the rest came from 16 surrounding villages. In the 18th century, the appearance of the church in Siemiatycze underwent gradual Latinization, although the
iconostasis remained. Latin began to appear in the services. The visitation protocol from 1774 indicates the emergence of an unknown Byzantine tradition of celebrating quiet masses at the side altars of Christ the Savior, the Mother of God, St. Paraskeva, and Saints Peter and Paul. Within the Russian Empire, elements of Latin origin were gradually eliminated from the Uniate church. The ritual unification was a preparation for incorporating Uniate structures into the
Russian Orthodox Church, which ultimately occurred at the
Synod of Polotsk in 1839. At that time, the church in Siemiatycze again became an Orthodox temple.
Orthodox church from 1840 to 1864 From 1840, the Orthodox church in Siemiatycze belonged to the Drohiczyn Deanery of the
Diocese of Lithuania. In 1851, the number of parishioners was estimated at 2,782 (with 386 from Siemiatycze), and by 1861, the number had risen to 2,846. Although Father Lacewicz did not support the conspirators' meetings at the rectory, he also did not inform Russian authorities that Orthodox parishioners were reading illegal Polish patriotic literature. After the uprising broke out, Father Lacewicz was captured by a Polish unit but was released following the intervention of the local Catholic parish priest, Father Roch Boguszewski.
Construction and operation of the brick Orthodox church in the Russian Empire '' above the entrance to the church By the 1860s, the deteriorating wooden church in Siemiatycze was in danger of collapsing. At the end of the 19th century, Orthodox Christians made up less than 10% of the population of Siemiatycze, where Jews dominated, comprising 75%. Returning parishioners worked to restore the church's furnishings lost during the war years. For example, residents of
Krupice funded a new Golgotha. By 1936, the parish had 5,914 members, including 589 from Siemiatycze itself, and from 24 surrounding villages. In 1953, Metropolitan
Macarius Oksiyuk of Warsaw and all Poland visited the parish. In 1966, in preparation for the church's centennial, the building was reroofed with zinc plates and repainted. Local families, the Koszewniks and Kuźmiuks, donated new liturgical vessels,
After 1989 On 7 December 1995, the church, along with its cemetery, guardhouse, and fencing, was registered as a historic monument (number A-110). The following year, the number of parishioners at Saints Peter and Paul Parish significantly decreased as new parishes were established in
Boratyniec Ruski and
Rogawka, as well as a second parish in Siemiatycze, dedicated to the Resurrection of Christ. On 17 August 2000, a copy of the
Panagia Portaitissa, donated by monks from
Mount Athos to the
Grabarka Holy Mount, was exhibited for veneration in the church. In 2003, a thorough renovation of the roof was completed, replacing it with copper sheeting. All seven church domes were replaced, and nine new crosses were installed, consecrated by Archbishop
Abel Popławski of Lublin and Chełm. The next Bishop of Siemiatycze, , was consecrated in this church on 8 October 2017. Since 2004, a Religious and Paraliturgical Song Review has been held annually in November at the church and, once completed, at the . The event features church choirs and groups performing Belarusian, Ukrainian, and Russian folk music. In 2021, the church received relics of its patrons – Saints Peter and Paul. == Architecture ==