Złoczów was destroyed by the Teutonic Knights in 1455 during the Thirteen Years' War. The town later belonged to the Potulicki family which provided it with a new Gothic castle in Renaissance style at the beginning of the 17th century. In 1619, Jan Potulicki issued a founding document for the church and parish of the Holy Assumption of Mary. Later it passed to the Grudziński family. In 1665 the town still had Magdeburg rights. The castle was destroyed during the Swedish invasion in 1657. The bombardment also destroyed other parts of the city including the town hall. A new church, still standing today, was founded there in 1664 by Andrzej Karol Grudziński. After the rule of the Grudziński family came to an end in 1688, the Działyński family came into power.