Jan Maria Michał Kowalski (25 December 1871 – 26 May 1942) was the first Minister Generalis (Minister General) of the order of the Mariavites. At the time of his selection, he was the most important person in this Christian movement. He was consecrated Bishop in 1909 by the Utrecht UnionOld CatholicArchbishop Gerardus Gul. In 1919 the Mariavites officially changed its name to the Old Catholic Church of the Mariavites. Bishop Kowalski later called himself Archbishop. Bishop Kowalski died during World War II in the Hartheim Euthanasia Centre located in Alkhoven by the city of Linz in Nazi occupied Austria. His successor was his wife, Bishopess Izabela Wiłucka. She was succeeded in 1946 by Bishop Józef Maria Rafael Wojciechowski. Wojciechowski died in April 2005 and was succeeded by Bishopess Beatrycze Szulgowicz.