Pope Pius V Biography

Pope Saint Pius V (17 January 1504 – 1 May 1572), born Antonio Ghislieri (from 1518 called Michele Ghislieri, O.P.), was head of the Catholic Church and ruler of the Papal States from 8 January 1566 to his death in 1572. He is venerated as a saint of the Catholic Church. He is chiefly notable for his role in the Council of Trent, the Counter-Reformation, and the standardization of the Roman rite within the Latin Church. Pius V declared Thomas Aquinas a Doctor of the Church.