Parish Church of the Assumption of the Blessed Virgin Mary in Ostrow - a former Roman Catholic church, built between 1843 and 1852 based on a design typical of churches in Galicia, now remains in ruins.

History
The parish in Ostrow (Ostrow Bełski) was erected in 1429, and from the beginning it was part of the Chelm diocese. Only after the partitions of the Polish-Lithuanian Commonwealth, in 1790, was it annexed by imperial decree to the Lviv archdiocese, where it remained until the end of World War II.

The first church in Ostrowa was wooden and little is known about its appearance. The earliest description of the temple dates only from 1603, when the building was in a poor state of repair and there was only one altar inside. At that time, the church bore the invocation of the Assumption of the Blessed Virgin Mary and St Sigismund. At the turn of the 17th and 18th centuries, the church was thoroughly renovated, and it is possible that a new church, also made of wood, was built. This church, too, began to fall into disrepair relatively quickly and in 1737, with the foundation of the then parish priest, Father Michał Królikowski, and with the help of the Great Crown Warden, Józef Sierakowski, a new wooden church was built on a brick foundation. A two-storey sacristy attached to the presbytery to the east was also built of brick, and a bell tower with three bells was erected in front of the façade. In 1762, the roof covering was replaced and the bell tower was repaired.

Almost from the beginning of the 19th century, efforts were made to build a new church. The cornerstone was consecrated by the Lviv Archbishop František de Paula Pištěk during his visitation of the parish on 19 June 1843. The shell of the building was ready in 1852, the consecration of the finished church of the Assumption of the Blessed Virgin Mary, St. Peter and Paul was held in 1852. The consecration of the Church of the Assumption of the Blessed Virgin Mary, St Tekla the Virgin and Martyr and St John of Dukla took place on 8 June 1858. Extensive renovations were carried out on the church in the 1930s and 1940s.

The church suffered during the Ukrainian Insurgent Army's attack on Ostrów on 31 March 1944, when residents took refuge in the temple. The building was then shelled, and in May 1944 Ukrainian Insurgent Army gangs mined the entire church. According to the parish priest's account of May 1948, two mines exploded and caused the façade and almost the entire tower to collapse. After the correction of borders in 1951 and the expulsion of Poles from Ostrów by the authorities of Soviet Ukraine, the last mass was held on 6 September and the church was closed on 17 September. Bands of the Ukrainian Insurgent Army then blew up the remains of the tower and the church fell into ruins.

Architecture
The church is located by the road, in the central part of the village. It is built of brick, rectangular in plan, with a single-nave body and a single-span chancel facing east. The interior, with divisions in the wall-pillar system, is covered with a jagged vault. There is a recessed music choir in the first bay of the body. The windows in the body and chancel are small, double arched windows.

The façade of the church is simple, with a massive three-storey tower on the axis, surmounted by an onion-shaped cupola. The lower part is covered with rustication.

Artistic issues
The church in Ostrow is an example of the use of so-called typical designs, spread in Eastern Galicia by the Austrian government. In its form and size it is closest to the design of a church for a thousand worshippers prepared for eastern Galicia in 1810 by the architect Maximilian von Cruss. The original contribution of the anonymous builder of the Ostrów church was the use of ogival windows and the simple closing of the chancel.