In 1650, Bogusław Leszczyński, in his hereditary village of Leszno near Warsaw, founded a church and monastery bonifratellom as it was then called the Brothers (Bonifratrów).

In 1713, Augustus II the Strong bought Morsztyn's palace as his residence and expanded it into neighbouring areas which included the monastery and church.

Work began in 1728 and a few years later, the Bishop of Poznań Jan Joachim Tarło dedicated the church and monastery.

In 1760, Prince August Aleksander Czartoryski, voivode of the Ruthenian province, built a new building for 34 patients and several ancillary rooms.

Also, the builder of the church, architect Jakub Fontana left 74,000 złoty for maintenance and to help the sick, in his will dated March 20, 1773.