Islamic armies ranged along the coasts of Africa, the Middle and Near East, toppling established powers, yearning “to bring all Europe within the dar al-Islam, the ‘House of Submission’ — submissive to the sharia law. Europe, as the land of the infidels, was the dar al-Harb, the ‘House of War’.
People in the city of Nicosia surrendered, “expecting the civilians to be spared, even as the Christian troops were enslaved. Instead, the Muslim attackers butchered every Christian they could find — 20,000 victims, murdered regardless of rank, sex, or age…”
The Muslim attackers set their sights on Famagusta. They proceeded to dig a huge network of criss-crossing trenches for a depth of three miles around the fortress, which provided shelter for their troops. August 1, Venetians had surrendered after Catholic defenders were outnumbered 7 to 1. They were reassured that they could leave Cyprus freely. However, the commander, Lala Kara Mustafa Pasha, broke his word, imprisoning the Venetians. On August 17th, the Venetian Commander Marco Antonio Bragadin was “flayed alive and his corpse hung on Mustafa's galley together with the heads of the Venetian commanders, Astorre Baglioni, Alvise Martinengo and Gianantonio Querini”. Christian youths were taken from their families, trained up in the art of war, converted to Islam, and given the power of the sword and the possibility of advancement.
As familiar as this now seems with the present massacres and youtube butchering by radical Islamic groups, this scenario occurred in 1571. In response, Pope Pius V promoted establishment of a "Holy League", a Christian coalition cobbled together from the reluctant Christian European states to rescue the Venetian colony of Cyprus and prevent the fall of Europe. Pope Pius called all of Europe to fast and an appeal to the Blessed Mother through taking up the power of prayer in the weapon of the Holy Rosary.
Fresh from conquering Famagusta, the Ottoman and Holy League fleets engaged in a battle off Lepanto on October, 7.
“It was the last battle at sea between "oared" ships, which featured the most powerful navy in the world, a Moslem force with between 12,000 to 15,000 Christian slaves as rowers. The patchwork team of Catholic ships was powered by the Holy Rosary of the Blessed Virgin Mary.”
This resulted one of the decisive turning points in the long Ottoman-Christian struggle, ending the Ottoman naval hegemony in a crushing victory for the Christian fleet, while the Ottoman fleet was effectively destroyed and thwarted from invading all of Europe.
“At the hour of victory, St. Pope Pius V, who was hundreds of miles away at the Vatican, is said to have gotten up from a meeting, went over to a window, and exclaimed with supernatural radiance: ‘The Christian fleet is victorious!’ and shed tears of thanksgiving to God.”
The Holy League credited the victory to the Virgin Mary, whose intercession with God they had implored for victory through the use of the Rosary. Andrea Doria, fleet admiral, had kept a copy of the "miraculous" image of Our Lady of Guadalupe given to him by King Philip II of Spain in his ship's state room.  “
“This image is now enshrined in the Church of San Stefano in Aveto, Italy. Not many know that at the Monastery of Our Lady of Guadalupe in Spain, one can view a huge Warship lantern that was captured from the Moslems in the Battle of Lepanto. In Rome, Look up to the ceiling of S. Maria in Aracoeli and behold decorations in gold taken from The Turkish galleys. In the Doges’ Palace in Venice, Italy, one can witness a giant Islamic Flag that is now a trophy from a vanquished Turkish ship from the Victory. At Saint Mary Major Basilica in Rome, close to the tomb of the great St. Pope Pius V, one was once ableto view yet another Islamic flag from the Battle, until 1965, when it was returned to Istanbul in an intended friendly token of concord.” 
The Victory over the Moslems at Lepanto was credited to the faithful prayers of the Rosary. Thus Pope Pius V instituted a new Catholic feast day on October 7 to liturgically celebrate the victorious Battle of Lepanto as Our Lady of Victory. In 1716, Pope Clement XI (who canonized Pope Pius V to sainthood in 1712) renamed this feast day as Our Lady of the Rosary, and extended it throughout the Universal Church.
Today, given our universal situation, we implore Catholics around the world to form another Holy Prayer League in solidarity and take in our hands our most powerful and effective weapons. Pick up your Rosary today and beseech Our Lady of Victory, Our Lady of the Rosary in earnest prayers to once again intercede on our behalf to end the slaughter and butchery of the Muslim factions intent on their jihad of destruction.
 H.W. Crocker III, Lepanto, 1571: The Battle that Saved Europe.
Morley Publishing Group, Inc. http://www.catholicculture.org/culture/library/view.cfm?recnum=7391
 Badde, Paul. Maria von Guadalupe. Wie das Erscheinen der Jungfrau Weltgeschichte schrieb. ISBN 3-548-60561-3.