Church of Our Lady of the Assumption is a former Calvinist church in Leszno dating back to the 17th century, noted for its exceptional half-timbered architecture. The church directly relates to the city's unique calvinist history. In the early 16th century, a community of Protestants who had been expelled from Bohemian territories found refuge in Leszno and settle there. They were specifically invited by the Leszczyński family, who had become imperial counts since 1473 and had converted to Calvinism. The arrival of the Bohemian Protestants as well as weavers from nearby Silesia helped the settlement to grow and made it possible to become a town in 1547 by a privilege according to Magdeburg Law granted by King Sigismund I of Poland.