Along the side of the right aisle is the Rosary Chapel, which stands in the spot occupied by the chapel by the same name in the ancient church of the Santissimo Salvatore. Its ceiling was completely decorated with frescoes illustrating the main events in the life of the Virgin Mary: the Annunciation, Nativity, her Presentation in the Temple and Wedding to Saint Joseph. Unfortunately these works are no longer visible, because they were destroyed when the church was rebuilt in the nineteenth century. The altar of the earlier Rosary Chapel held the painting, now kept in the Civic and Diocesan Museum of Montalcino, of Our Lady of the Rosary commissioned in 1572 to the Sienese painter Tiberio Billò of the Congregation of the Holy Rosary which was active since 1569. Thus the commission was awarded the year after the victory of the Christian fleet over the Turks in the Battle of Lepanto, won on 7 October 1571 thanks to the intercession of the Virgin Mary, because of which Pope Pius V instituted the feast of Our Lady of the Rosary. The painting shows the Virgin and Child between Saints Dominic and Catherine of Siena (the practice of reciting the Rosary was spread mainly by the Dominican order) and some bishops. The painting, enjoyable for the liveliness of its colors, merits mention above all because of its devotional importance. On the altar of the chapel now is a splendid example of . . .