The two founders having obtained the Pope's blessing and certain indulgences, returned to France, presented themselves to the king, Philip Augustus, who authorized the establishment of their Order in his kingdom, and favoured it with his liberalities. Gauthier III., lord of Châtillon, gave them land whereon to build a convent. Their number increasing, the same lord, seconded by the king, gave them Cerfroid, near Grandlieu, the place in which S. John and S. Felix concerted the first plan of their institute. It is situated in Brie, on the confines of Valois. This house of Cerfroid, or De Cervo frigido, was the chief of the order. The two saints founded many other convents in France, and sent several of their religious to accompany the counts of Flanders and Blois, and other lords, to the Crusade. Pope Innocent III. wrote to recommend these religious to the Emir of Morocco; and S. John sent thither two of his religious in 1201, who, on the first voyage, redeemed one hundred and eighty-six Christian slaves. The year following, S. John went himself to Tunis, where he purchased the liberty of one hundred and ten more. He returned into Provence, and there received great charities, which he carried into Spain, and redeemed many in captivity under the Moors. On his return he collected large alms among the Christians towards this charitable undertaking. His example produced a second order of Mercy, instituted by S. Peter Nolasco, in 1235.
S. John made a second voyage to Tunis, in 1210, in which he suffered much from the infidels, enraged at his zeal and success in exhorting the poor slaves to patience and constancy in their faith. As he was returning with one hundred and twenty slaves he had ransomed, the barbarians took away the helm from his vessel, and tore all its sails, that they might perish in the sea. The saint, full of confidence in God, begged Him to be their pilot, and hung up his companions' cloaks for sails, and, with a crucifix in his hands, kneeling on the deck, singing psalms, after a prosperous voyage they all landed safe at Ostia, in Italy. Felix, by this time, had greatly propagated his order in France, and obtained for it a convent in Paris, in a place where stood before a chapel of S. Mathurin, whence these religious in France were called Mathurins.