The Oświęcim Chapel (Polish: Kaplica Oświęcimów), dedicated to the Blessed Virgin Mary and St. Stanislaus of Szczepanów, is an extension to the Gothic Franciscan Church in Krosno (pl:Kościół i Klasztor oo.

The main furnishing is the altar from 1890 (a faithful copy of a mid-17th century original) with ornaments, woodcuts and paintings dating from the chapel's foundation.

[6] The inscription on the sepulchral chapel reads (in Latin) ... to God's eternal remembrance, dedicated to noble Anna z Kunowy Oświęcimówna, most beloved sister, from her most saddened and sorrowful brother Stanisław z Kunowy Oświęcim (...) as a sign of the eternal love that even death cannot stop, steeped in sadness and grief, also to his ancestors, successors and descendants, this chapel as a house of prayer for the living and a grave as a place of eternal rest for the dead, founded in the year 1647 from the birth of our Lord,[9] gave rise to the legend of incestuous love between brother and sister, for the first time recorded in 1812.

According to the most popular version Stanisław, courtier of King Władysław IV Vasa after returning from his diplomatic missions, fell in love with his long lost younger sister.

Some versions say that Anna was poisoned by his mother or by a rejected suitor, waiting for the return of her brother, or at the news that the Pope blessed their relationship[6] (as marriages were forbidden to the seventh degree of kinship).

[7] The fact that in February 1647 he attempted to become a Steward of Prince Sigismund Casimir Vasa may also indicate his imminent return to earthly reality and his need to seek solace.

Stanisław was still alive 10 years after his sister's death; he fought at Berestechko and during the Deluge, and died during the invasion of the Polish–Lithuanian Commonwealth by Prince George II Rákóczi of Transylvania in 1657.