Unfortunately, research on furnishings of the St. Martin's church carried out so far, due to lack of archival records on the constructors, does not even try to determine a circle of potential authors of the reredoses and its sculptural decor. The sculpture was created in the second half of the 18th century and it depicts St. John, who was a disciple of Saint John the Baptist and then a beloved disciple of Christ. The saint was displaced to the island of Patmos, where the book of Revelation was written. He then returned to Ephesus and wrote the fourth Gospel and three canonical letters. He died when he was about 90 years old.
Maria Działo, "Sculpture of St. John the Evangelist", [in:] "The Sacred Lesser Poland Heritage", 2021, source: https://sdm.upjp2.edu.pl/en/works/sculpture-of-st-john-the-evangelist