In the mid-16th century, the feudal lord of the area was Stanisław Ruszkowski (1529-1597), cavalry captain in expeditions of Stefan Batory against Moscow, knight of Sieradz, and Warrant Officer of Kalisz, who is buried in the monastery Order of Cistercians in Koło, where his tombstone is preserved. However, Złoczew owes its urban character to his son, Andrzej Ruszkowski (1563-1619), knight of Kalisz and owner of the Nowa Wieś, Barczew, and Ruszków. In 1600, he brought the Order of Cistercians to Złoczew, building their church and monastery, and in 1601 he funded the construction of the parish church for Złoczew.