The reredos originates from the non-preserved wooden chapel of the Transfiguration, located nearby the church. The episcopal visitation from 1748 states that there is one altar with the painting of Transfiguration of Jesus. Due to the poor condition, the chapel was soon demolished, and the reredos itself, without the altar mensa, was moved to the Church of Saint John the Baptist. It probably took place between 1791 and 1828. The reredos was created around the date of the consecration of the Chapel of the Transfiguration, i.e. 1642. This is also confirmed by the stylistic analysis of the work, which is a characteristic example of the wood carving of this period, decorated with a number of motifs related to the ferrule ornament. The subject of the painting in the main area refers directly to the chapel's invocation. The iconography of the finial presents the Vision of Saint John of Kęty (1390-1473), one of the most popular Polish saints.
Maria Działo, "Side altar of the Transfiguration", [in:] "The Sacred Lesser Poland Heritage", 2023, source: https://sdm.upjp2.edu.pl/en/works/side-altar-of-the-transfiguration