The Church of St. John the Evangelist and Our Lady of Częstochowa in Bartoszyce, also known as St. Johanneskirche von Bartenstein, is a Gothic structure dating back to the mid-14th century and is one of the oldest monuments in the city. Located in the Old Town, the church was likely built in 1332, coinciding with the founding of the town. Over the centuries, the building was expanded several times, acquiring a three-nave layout and numerous chapels. It was consecrated in 1487 and from 1525 served the Evangelical community. After being damaged during World War II, the church was rebuilt between 1946 and 1958 and converted into a Catholic place of worship. Today, it is in good condition, surrounded by greenery and an historic rectory from the 18th/19th century. Architecturally, the church retains Gothic features, including a tall tower and a three-nave interior, as well as 16th-century organs. The interior is distinguished by a polychromed crucifix and a beautifully decorated altar, parts of which damaged during World War II are now housed in the Museum of Warmia and Mazury. Registered as a historical monument, this church is an important element of Bartoszyce's historical landscape and a testament to the region's rich history. Interestingly, its original altar may have been one of the few examples of Netherlandish sacred art in Prussia, highlighting the church's significance in the context of regional culture.