The village had a parish church, and castle fortification built during 1327–1330, which formed part of the Duchy defense system, surrounded by a rampart and moat, the castle had two wings and a bastion with 2–3 metre thick walls. The castle ruins remained visible until the mid-1930s, when it was sold and gradually dismantled for building materials, sporadic parts of the castle foundations remain. The first wooden church was built about 1326, and rebuilt during the 16th century after suffering fire damage. In 1559, the parish Catholic church was Reformed (to Calvinism), introduced to the parish by a member of the House of Saszowski, the nobleman and Burgrave of Kraków Jakub Saszowski of Gierałtowic. The church remained so until 1658, when during the Swedish Deluge, it was restored the Roman Catholic faith. The majority of village inhabitants, nevertheless, remained faithful to the Reforms. Although Kozy was in the Kingdom of Poland, the village community were mostly German-speaking, embraced the Protestant Reformation, and would thus come under persistent attack from the Catholic Church during and after the Counter-Reformation.