The Barcelona merchant Pedro Nolasco (1189-1245) used his wealth to free prisoners and slaves.

According to tradition, once night the Virgin appeared to him and asked him to found an order dedicated to the redemption of captives: the Order of the Virgin Mary of Mercy.

The Mercedarians were obliged to takes the usual vows of obedience, poverty and chastity, and also a fourth vow, promising to free Christian captives and even to risk their lives, if necessary.