The construction of the church of St. John the Evangelist and Our Lady of Częstochowa in Bartoszyce began around 1332 with the location of the town of Bartenstein, which replaced the earlier settlement on the opposite bank of the river. The first mention of it comes from 1345. In 1487, the church was consecrated again, perhaps because of the destructions of the Thirteen Years’ War. From 1525, after the secularization of Prussia, it served the Evangelical community of the town, which then constituted the majority of Bartoszyce. It was rebuilt in 1676, and in 1732 the church tower was transformed. It suffered major damages during the Second World War, especially the stellar vaults. The reconstruction and renovation was carried out in the years 1946-1958.
Despite the rebuildings made in the 17th and 18th centuries, the church still retains its original, gothic character of a three-nave basilica, with much lower aisles. On the western side there is a four-sided, decorated with a blendes tower, the eastern side is ended with a polygonally closed, buttressed chancel. It is equal in height and width to the central nave and has windows located on two floors. In 1406, the chapel of St. Mary the Virgin was added to the church, and before 1414 the chapel of St. Anne. In the first half of the 16th century, next to the presbytery, another chapel was founded by the bishop of Warmia. The interior of the church is decorated with a stellar vault, carefully reconstructed after the destruction of the Second World War.