The reformed church or St. Jan is a late-Gothic cruciform church with a choir from the mid-15th century, a transept built in ca. 1470 and widened in the eaely-16th century and a three-aisled pseudo-basilican nave that was completed in ca. 1500. In ca. 1465 a tower was built. The church was built at a strange location, as a border ran through it, with the western part with the tower standing in the village of Besoyen, Holland, while the eastern part stood in Waalwijk, in the duchy of Brabant. At the end of the 16th century, in the Eighty Years War, the church was badly damaged. After forty years of war the Twelve Years-truce (1609-1621) gave Waalwijk the opportunity to restore the damaged church. The rebuilding of the church was intended to be a matter of prestige and was financially supported by Isabella, governor of the Southern Netherlands. Work had to be restricted to the part of the church that stood on Brabant soil. Besoyen, like the rest of Holland, had officially become protestant and built a small church of its own in 1610.
In 1616-1617 the church was repaired and given a new front. After the war continued in 1621 the church changed hands several times, and became protestant permanently in 1648, when the war ended and the duchy of Brabant was divided between Spain and the Republic.