Every year, Our Lady of the Rosary is celebrated on October 7. This liturgical solemnity is not linked to any particular moment in the history of salvation, but commemorates the victory of the Christians at the Battle of Lepanto in 1571, obtained, according to the then Pope St. Pius V, thanks to prayer of the Rosary. This event gave decisive impetus to this devotion and developed its iconography, which links the Virgin Mary and Saint Dominic. This documentary explores the historical, spiritual and pastoral implications of this prayer, from the Fanjeaux region, at the origins of the Dominican order, where, according to tradition, the Virgin Mary gave the Rosary to St. Dominic, to Lourdes, where the apparitions to Bernadette are inextricably linked with this prayer, and where the basilica dedicated to Our Lady of the Rosary was built against the grotto, to Pompeii, where Blessed Bartolo Longo, a true apostle of the Rosary, had a huge shrine built in its honor and made a major contribution to the city’s social development thanks to its dissemination. Finally, this film shows that the Rosary is an immersion in the purest content of the Christian faith, brought to us by the prayer of Mary. Our Lady of the Rosary.