Here’s a complete review of the , covering their purpose, structure, spiritual significance, and practical use within Legionary devotion. 1. What Is the Legion of Mary Tessera? The Tessera (Latin for “square” or “token”) is a small card or prayer booklet given to active Legion of Mary members after their probation period. It contains the short daily prayers of the Legion, including the Catena Legionis (“Chain of the Legion”) — a set of prayers that incorporates the Joyful Mysteries of the Rosary.