The original representation of Our Lady of Mercy is the typical image of Our Lady of Ransom, the patroness of the Mercedarians. She holds the Mercedarian scapular in her right hand. The left hand holds the chains, the typical attribute of Our Lady of Ransom.
The origins of Our Lady of Mercy (Nuestra Señora de la Merced) date back to the early 13th century in Spain. A secular friar named Peter Nolasco (now Saint Peter Nolasco) from Barcelona began his work to free Christian captives being taken by the Moors to northern Africa as slaves. With his own money, he organized expeditions to negotiate the release of these captives and slaves. His experience as a merchant proved a valuable skill in negotiating their release. Out of money, he formed groups to collect charity for the captives.
On the night of August 1 and 2 in the year 1218, the Virgin Mary appeared to Saint Peter Nolasco asking him to form an Order dedicated to the release of all Christian captives. Together with Saint Raymond of Peñafort, they founded the Order of Our Lady of Mercy in Barcelona on August 10, 1218 with the consent of Jaime I the Conqueror, King of Aragon.
Pope Gregory IX approved the Order in 1235 under the Rule of Saint Augustine under the canonical foundation of the Bishop of Barcelona, with support of the military power of Jaime I. Members of the Order were obligated to give themselves as hostages in exchange for the liberation of the Christian captives if they did not have the funds necessary to negotiate their release. The four vows by the Order include poverty, chastity, obedience, and the fourth vow. This vow was one that required its members, as a last resort, to give up their own life in exchange for any who might lose their faith.