Pope Pius V was elected to lead the body of Christ and zealously worked to implement the renewal of the Church mandated by the Council of Trent. As a Dominican friar devoted to a life of prayer, fasting and poverty, he called the princes of the church back to a simpler and holier way of life — a message that was not well received by bishops and priests who had become accustomed to the wealth, power and freedom they enjoyed while collaborating and reveling with the royalty of the day.
Pius was tireless in pursuing the broad reforms called for by the Church fathers. To address the lack of knowledge of faith among Christians, he created a new catechism and established the Confraternity of Christian Doctrine (CCD) for forming the young in the faith. He founded new seminaries for providing proper training for priests. To elevate the prayer life of the Church, he released a new missal and a new breviary. The 1570 edition of the Roman Missal he promulgated was used for 400 years until St. Paul VI revised it after Vatican II.