Because of his intellectual abilities and desire to lead a religious life, his parents let him leave home at 13 to go to the Seminário de Belém, at Cachoeira in Bahia.
When the Jesuits had to return to Portugal, the seminary was closed down.
At 18, Antônio returned home to Guaratinguetá. His loving mother had died two years before. Since his desire to serve God had not changed, shortly afterwards he went to Convento Franciscano de São Boaventura de Macacu, in Itaboraí, in the Rio de Janeiro area. He adopted the religious name of Antônio de Sant’Anna Galvão in honor of his family’s devotion to that saint.
He was professed as a Franciscan in 1761, and the following year, ordained priest in Rio de Janeiro. He was transferred to the Convento de São Francisco in São Paulo, to finish his studies in philosophy. On his trip there, he was able to stop on at Guaratinguetá to celebra te a “First Mass” in his home town. It was a great joy for his family and all those who participated. Thus he began his priesthood celebrating a mass in the same church in which he had been baptized.