The painting is a work of undetermined authorship. Its creator might have been one of painters from Lesser Poland, specialising in religious themes, active in the second quarter of the 17th century. The time when the work was created is probably the same as the time when the altar of Saint Anne, i.e. the painting could have been created in 1636. Michael the Archangel depicted in the painting was the leader of the angelic choirs and during the angels' revolt, he first went into battle and won their leader, Lucifer. In iconography, he is depicted in soldier's clothing with the devil at his feet and with a sword (or spear) and scales in his hand.
Justyna Kuska, "St. Michael the Archangel", [in:] "The Sacred Lesser Poland Heritage", 2021, source: https://sdm.upjp2.edu.pl/en/works/st-michael-the-archangel-2