Saint John was born, probably in 1540, in Fontiveros, near Avila in Spain. His father died when he was very young and he had to move with his mother from one place to another, while he tried as best he could to continue his education and, at the same time, to earn a living. In Medina in 1563 he was clothed in the Carmelite habit and, after a year's novitiate, was given permission to follow the unmitigated Carmelite Rule.