Pius V
January 17, 1504 — May 1, 1572 · Feast day: April 30
Born Antonio Ghislieri to a poor family in Bosco, he entered the Dominican Order at fourteen and served as a reforming inquisitor before being elected pope in 1566. He standardized the Latin liturgy through the Roman Missal of 1570, excommunicated Elizabeth I, and organized the Holy League whose defeat of the Ottoman fleet at Lepanto he credited to Marian intercession — establishing what became the Feast of Our Lady of the Rosary.