"The Epistles & Hymn of Saint Patrick" by Thomas Olden, Dublin 1876

 Used as a Lorica ( A “lorica” was a mystical garment that was supposed to protect the wearer from danger and illness, and guarantee entry into heaven. ) for protection by St. Patrick from the pagan Druids that lay in ambush to intercept and kill him and his companions on their way to the king's court. They did not see Patrick pass, only a doe followed by her twenty fawns. Hence the name, "Deer's Cry".