One of the most beautiful churches in the region, designed by prominent architect Pawel Antoni Fontana, was built between 1753 and 1763. The founders were the owners of the surrounding landed estates, Marianna of Radzimiński Wolska and Waclaw Rzewuski. The late Baroque temple, with an octagonal main nave and an elliptical enclosure with a row of chapels, is a perfect combination of two plans – longitudinal and central (similar churches Fontana, as an architect of the Sanguszko magnate court, also designed in Włodawa and Lubartow). The mighty western façade is decorated with tall towers on the corners, and in front of the church stand statues of St. Joseph Kalasantego and Our Lady of Grace. The builder of the temple was Tomasz Rezler, and among the many authors of the rich Baroque-Rococo interior design were the greatest masters of the era: sculptor and woodcarver Michal Filewicz, and painters Szymon Czechowicz and Jozef Mayer.
Interestingly, the church stands on the site of an earlier Roman Catholic cathedral, built in 1417 by King Wladyslaw Jagiello as a votive offering for the significant participation of the Chełm Land Ensemble in the Battle of Grunwald. The original church served as a cathedral until 1490, when the seat of the bishopric was moved to Krasnystaw. Adjacent to the Church of the Propagation of the Apostles is a large complex of Piarist monastery buildings from the first half of the 18th century. The Piarists were present in Chelm from 1667 to 1864, running a parish, a school for noble sons (one of the first colleges in Poland), a library and a hospital for the poor. Currently, part of the former college is occupied by the Wiktor Ambroziewicz Museum of Chelm Land.
A visit to the church should be planned for Sunday. On that day, after the 10:00 am Mass, it is possible to visit the Parish Museum. It gathers many valuable exhibits, including a 17th-century painting “St. Augustine fights heretics,” a wooden tabernacle from 1756 from the high altar, flags, reliquaries (of St. Isidore, Blessed Fr. Jerzy Popieluszko and the tree of the Holy Cross).