October 7th, Feast of the Most Holy Rosary of the Blessed Virgin Mary:
October 7 is the anniversary of the glorious victory won in 1571 by the Christian forces over the Turkish fleet at Lepanto. This triumph of the Cross over the Crescent was universally attributed to the powerful intercession of the Mother of God, whom Pope Pius V fervently invoked with her Rosary in his hand, and to whom the prayers of all Christendom were addressed.
Two years after this great favor had been obtained, Gregory XIII instituted an annual feast of thanksgiving to be celebrated on the First Sunday of October in all churches where an altar in honor of the Blessed Virgin of the Rosary had been erected. From being a local festival this celebration gradually spread and became general, until Leo XIII raised it to the rank of a double of the second class for the whole Church.
The devotion of the Rosary of the Blessed Virgin Mary dates at least from the Twelfth Century. The glory of having spread this form of prayer with such extraordinary success is certainly due to the Dominican Order, and, owing to their zeal, the Rosary soon became the most popular devotion throughout the Christian world.
The Holy Rosary as it is now recited, and enriched with great indulgences, represents, after the Divine Office, what may be described as the popular Breviary of the Gospel. By meditating on the appropriate mysteries, it may be adapted to the Liturgical Cycle, and because it unites vocal with mental prayer the Rosary is regarded as the most beautiful and approved devotion of the Latin Church.
Today the Holy Rosary of the Blessed Virgin Mary is recited by many even who are not Catholics because it is recognized as one of the most powerful ways to pray for God's help. If you want to look into how this powerful set of vocal and mental prayers can overcome the evil we face follow this link.
If it were not for some very important victories in previous centuries by Christianity over the Muslims we might all be wearing some kind of cloth wrapped around our heads and jabbering in some Arabic dialect. The battle of Lepanto was probably THE most important of these victories, and it was very evident at the time what was responsible, and who was responsible for that victory.
This is an excerpt from the story of the life of Pope St. Pius V found in the Catholic Encyclopedia.
He worked incessantly to unite the Christian princes against the hereditary enemy, the Turks. In the first year of his pontificate he had ordered a solemn jubilee, exhorting the faithful to penance and almsgiving to obtain the victory from God. He supported the Knights of Malta, sent money for the fortification of the free towns of Italy, furnished monthly contributions to the Christians of Hungary, and endeavoured especially to bring Maximilian, Philip II, and Charles I together for the defence of Christendom. In 1567 for the same purpose he collected from all convents one-tenth of their revenues. In 1570 when Solyman II attackedCyprus, threatening all Christianity in the West, he never rested till he united the forces of Venice, Spain, and the Holy See. He sent his blessing to Don John of Austria, the commander-in-chief of the expedition, recommending him to leave behind all soldiers of evil life, and promising him the victory if he did so. He ordered public prayers, and increased his own supplications to heaven. On the day of the Battle ofLepanto, 7 Oct., 1571, he was working with the cardinals, when, suddenly, interrupting his work opening the window and looking at the sky, he cried out, "A truce to business; our great task at present is to thank God for the victory which He has just given the Christian army". He burst into tears when he heard of the victory, which dealt the Turkish power a blow from which it never recovered. In memory of this triumph he instituted for the first Sunday of October the feast of the Rosary, and added to the Litany of Loreto the supplication "Help of Christians". He was hoping to put an end to the power of Islam by forming a general alliance of the Italian cities Poland, France, and all Christian Europe, and had begun negotiations for this purpose when he died of gravel, repeating "O Lord, increase my sufferings and my patience!" He left the memory of a rare virtue and an unfailing and inflexible integrity. He was beatified by Clement X in 1672, and canonized by Clement XI in 1712.
For some history of the area http://www.newadvent.org/cathen/09181b.htm