Pope St. Pius V in the year 1571 instituted the memorial to commemorate the miraculous victory of the Christian forces in the Battle of Lepanto on October 7, 1571. The pope emphasized the power of Mary's intercession as greater than the arms of war.
Entrusting self, work and evangelizing efforts to Mary's protection has become characteristic of the Church. In 2005 on the eve of an earlier Synod of Bishops, Pope Benedict did "entrust the work of the Synod to Mary." Before doing so he recalled the efforts his predecessor to revive praying the rosary:
This ancient prayer is having a providential revival, thanks also to the example and teaching of the beloved Pope John Paul II. I invite you to reread his Apostolic Letter Rosarium Virginis Mariae and to put into practice its directions on the personal, family and community levels.
We entrust the work of the Synod to Mary: may she lead the entire Church to an ever clearer knowledge of the proper mission of service to the Redeemer truly present in the Sacrament of the Eucharist. [Angelus, 2 October 2005]
The rosary is a prayer of protection in which we meditate on the mysteries of our Lord Jesus, turning them over in our hearts after the example of his Blessed Mother, who knew her son's incarnation, passion, resurrection and ascension in the most intimate ways.
Wiki-image of a scene of the Battle of Lepanto is in the public domain.