The
Royal, Celestial and Military Order of Our Lady of Mercy and the Redemption of the Captives, also known as
Our Lady of Ransom (, abbreviated
O. de M.) is a
Roman Catholic mendicant order established in 1218 by
St. Peter Nolasco in the city of
Barcelona, at that time in the
Principality of Catalonia (
Crown of Aragon), for the redemption of
Christian captives. Its members are most commonly known as
Mercedarian friars or
nuns. One of the distinguishing marks of the Order of the Blessed Virgin Mary of Mercy is that, since its foundation, its members are required to take a
fourth vow to die for another who is in danger of losing their faith. The Order exists today in 17 countries.