• It is a lay Catholic association whose members are giving service to the Church, on a voluntary basis, all over the world.

• It was founded in Myra House, Francis Street, Dublin, Ireland, on September 7, 1921.

• It has about 2,250,000 active members in over 160 countries.

• It is at the disposal of the bishop of the diocese and the parish priest.

• It is organized on the model of an army, principally the army of ancient Rome.

• The official handbook of the Legion has been published in at least 50 languages.

• The object of the Legion is the glory of God through the holiness of its members developed by prayer and active apostolic work.

• The basic unit of the Legion is called a praesidium, a Latin word used to designate a detachment of the Roman Legion performing special duty, a section of a military line, a fortified post, a garrison.

• Each praesidium is named after a title of Our Blessed Lady (for example, Our Lady of Mercy), or one of her privileges (The Immaculate Conception) or an event in her life (the Visitation).

• There are two (2) types of membership: active members who must attend a weekly meeting and perform weekly work obligation of at least two hours, and, auxiliary members or praying members .

• Any practicing Catholic who is willing to fulfill the obligations of membership in the proper spirit may belong to the Legion. Senior members must be 18 years of age, and junior members are those under 18. Persons of any age may be auxiliaries if they are able to say the required prayers.