Orphaned at a very early age, he renounced his inheritance in favour of an uncle and distributed what goods he had among the poor and set off on a pilgrimage to Rome. In Italy, he devoted himself to treating victims of the plague and ended up catching the disease himself. He then withdrew to a forest near Piacenza (Italy). According to legend, he was helped by an angel and a dog which would bring him food and remained faithful until he was cured. Disfigured by the disease, he returned to his homeland where he was imprisoned as an Italian spy as nobody recognised him. He was found guilty and died in prison. It was then that the birthmark on his chest was recognised.
In this portrayal, he dresses as a pilgrim (with staff, broad rimmed hat, gourd and bag), revealing his leg with the injuries inflicted by the plague and accompanied by a dog. His life is set out in four 16th century panels found in the Museum of São Roque.