The painting is a work of undetermined authorship. Its creator could be one of Lesser Poland painters specialising in religious painting, operating in the second quarter of the 17th century. The time of creation of the work is probably the same as the time of creation of the altar of Saint Anne, i.e. the painting could have been painted in 1636. The image presents Saint Martin of Tours, who lived in the 4th century and became a Roman legionary as a young man. During military service in Gaul, Christ appeared to him in the form of a half-naked beggar, to whom Martin gave half of his soldier's robe. In 371, the future saint was elected Bishop of Tours. In Christian iconography, St. Martin is most often depicted as a man in Roman legionary's clothing, riding a white horse. The saint is usually depicted when he shares his robe with the beggar.
Justyna Kuska, "St. Martin of Tours", [in:] "The Sacred Lesser Poland Heritage", 2021, source: https://sdm.upjp2.edu.pl/en/works/st-martin-of-tours-1