Jan Maria Michał Kowalski (1871-1942) was a Catholic priest – at least to begin with. Born in Latowicz, Poland, he was ordained in 1897, serving in several parishes before being assigned to the Capuchin church in Warsaw in 1900. A friend of his from seminary introduced him to a secret order of priests, the Congregation of Mariavites. This was organised around the private revelations of a nun, Maria Franciszka Kozłowska, who had begun having visions in 1893, centring around what she called “The Work of Great Mercy” (but quite different from St Faustina’s similarly named devotion).
Although there were a number of priests involved, Mother Maria was in charge of the Congregation, and in 1903 appointed Fr Kowalski as priests’ superior. All of this had been in secret because of government regulations regarding religious life in Russian-occupied Poland. But that year Mother Maria directed the priests of her group to seek approval from the Church. Examining her alleged revelations, Pope St Pius X ordered the group to disband; they refused, and so were excommunicated in 1906. In 1909, Kowalski was consecrated an Old Catholic bishop by that church’s archbishop of Utrecht. From then until Mother Maria died in 1921, the fledgling Mariavite Old Catholic Church slowly grew in numbers and organisation.
With Mother Maria’s death, Kowalski moved into a higher gear. The following year, he married Mother Maria’s replacement, and in 1924 announced that the Holy See was now in Płock with him, rather than Rome. Over the next decade, his newfound infallibility allowed him to declare that Mother Maria had been the incarnation of the Holy Ghost. There were also extensive liturgical changes; but the most exciting innovation was “mystical marriages” between priests and Religious sisters – children from these unions were held to be immaculately conceived.
For Archbishop Kowalski, however, a terrible fate was in store – he died in the Hartheim Euthanasia Centre.