The feast of Our Lady of the Rosary is one of many in Western and Eastern Christianity that commemorate the Holy Virgin's intercession during a time of strife. In this case, in 1571 the Ottoman Empire was seeking to expanding its reach into Italy, the Atlantic, and possibly the Americas. A Christian navy called the Holy League, gathered from maritime states in southern Europe, sailed to confront the Ottoman Navy. Knowing the Christian forces were at a great disadvantage, Pope Pius V called for all of Europe to pray the Rosary for victory, and led a rosary procession in Rome. The Holy League turned back the Ottomans, and in honor of this victory the Pope instituted the feast of Our Lady of Victory, later renamed to Our Lady of the Rosary and celebrated annually on October 7th.
Learn more: https://www.franciscanmedia.org/our-lady-of-the-rosary/
Our Lady of the Rosary, Pray for Us!