In the second half of the 16th century, Poland became the scene of the Protestant movement. Already Andrzej Górka showed a friendly attitude towards Protestantism and his sons became devoted Protestants. The new religion developed in Osieczna to such an extent that Stanisław Górka (Andrzej's son) deprived the Catholics of their parish church and gave it to the Protestants. Consequently, religious strife and conflicts started in Osieczna.
The development of Protestantism was enhanced not only by the favourable attitude of the owners of the town but also the increasing number of German settlers.
After Stanisław Górka's death in 1592, Osieczna was inherited by Andrzej Czarnkowski. The new owner managed to settle the religious conflicts. Catholic masses could be celebrated again, and Catholic and Protestant services were probably held in turns in the same parish church.
The church returned to the Catholics only in 1628 thanks to Adam Olbracht Przyjemski, who invited the Father Reformersto Osieczna and gave the church back to its rightful owners.
We can infer from the document issued by A. Przyjemski in 1635 that the Protestant church already existed at that time. It burnt up in 1656 but was later rebuilt.
In 1793 the Protestant church was gutted to a considerable extent by a disastrous fire. At the request of Pastor Gustav Buchner, Heinrich Burkhard Abbeg, owner of the Osieczna estate, bequeathed by will 30,000 marks to the construction of a new brick Protestant church and 15,000 marks to the construction of a new school for children of this denomination.
The new brick church was built in the neoromanesque style in 1900. The length of the church was 26 metres and the height of its tower 46 metres. When the church was built, Albert Emil Taube was the pastor of the parish.
There were not many Protestants in adjacent villages, so the parish was exceptionally extensive. It included all villages in the neighbourhood: Trzebania, Wyciążkowo, Gronówko, Goniembice, Wolkowo, Drzeczkowo, Popowo Wonieskie, Sulejewo, Zgliniec, Ratowice, Berdychowo, Grodzisko, ŚŚwierczyna, Łoniewo, Dobramyśl, Frankowo, and Kąkolewo.
In the 1930s the parish numbered 550-600 members. At the church there was a choire and the Young Men's and Young Women's Association. 
All worshippers also composed one association under the name "Der Evangelische Kirchenverein", which served different purposes. The life of the whole German minority centred around its church and parish.
In 1945 all the Germans had to leave Osieczna. The evangelic church was unused. The bells were taken to the Catholic parish church. There were many proposals for the use of the building, including converting it into a cinema, but none of them was implemented.
Finally the church was demolished in the 1970s. Its demolition was probably one of the biggest mistakes in the history of the town. The church was a sturdy building, and its lofty tower embellished the town.
This beautiful and strong building was thoughtlessly pulled down for the sake of some ideas, which are difficult to understand today.
The preserved foundation is the only trace of the demolished church, whose place is now occupied by a dwelling house. The once well-kept area around the old church lost its old charm.
The photograph on the left shows the Protestant church from the east, and the photograph on the right from the south.
The photographs come from Janusz Wróblewski'c collection.
The article was based on the book Osieczna i jej dzieje by St. Jędraś, Osieczna - Leszno 1991, and the typescript Osieczna - zarys historyczny by Father Edward Frankiewicz.
