Around 1810, the head man on a boat which was coming from Cuiabá, “tied up for the night at Potunduba, on the banks of the Tietê river” (in the county of Jaú), Manoel Portes, as he had whipped one of his crew, was mortally stabbed by this man. Feeling that his end was drawing close, Manoel Portes called out for Friar Galvão, so that he could make a confession.

His crew were amazed when the monk appeared suddenly at that desert area. He approached the dying man, heard his confession, listened to his last words, gave him absolution and then disappeared, leaving the crew bewildered.

At that same time, Friar Galvão was preaching in a church in São Paulo. He interrupted his sermon, asking for help to pray with him for the salvation of a dying soul who was far away. A chapel keeps the memory of this episode being a center of devotion to Friar Galvão.