The Blessed Virgin Mary has entered openly into the fray of the battle between good and evil when she appeared to St. Catherine Labouré, a novice of the Sisters of Charity at Rue de Bac in Paris, and made her coin a medal with her effigy on it: Mary stands on the world globe, with her feet crushing the head of the Serpent (the devil) - as was announced in Genesis - and with her arms wide open giving out bright rays of light, to mean the many graces that she is showering all over the world.
Around her image is the inscription: O Mary, conceived without sin, pray for us who have recourse to you. This medal has a special place in the Legion of Mary. It features prominently in the standard (vexillum) of the Legion. Around it every day the Legionaries all over the world recite the Catena Legionis, viz.
Our Lady’s Magnificat with this antiphon: “Who is she that comes forth as the morning rising, fair as the moon, bright as the sun, terrible as an army set in battle array?” It is the battle cry of the Legionaries, with Mary at their head, against Satan and his wiles. And they are not alone.