Pope St. Pius V is best known for implementing the decrees and spirit of the Council of Trent, which standardized the Church’s response to the Protestant Reformation.

He was born Antonio Ghislieri in 1504 near Milan, Italy, and was a shepherd as a youth until he entered the Dominican order at the age of 14 and took the name Michele. He was ordained a priest in 1528, and was assigned to lecture at the university in Pavia. He taught there for 16 years, and led several Dominican houses.

His leadership was marked by reformist zeal—he helped discipline communities that had grown lax—and he was appointed an inquisitor. Over time, he was promoted as “supreme inquisitor” and it was from this position that he even dared to rebuke his predecessor, Pope Pius IV, for extravagance and nepotism. When Pius IV died, Michele was elected pope at the age of 62 and took the name Pius V.

As pope, he worked to implement the teachings of the Council of Trent, which was called in response to the Reformation. One of his decisions was to standardize the Mass in Latin—in 1570, he promulgated an edition of the Roman Missal that served the Church for 400 years, until Vatican II.

Pius V also clashed with Queen Elizabeth I, which escalated the conflict with the English throne and led to her excommunication and the active persecution of Catholics in that nation.

To consolidate the Church’s power, Pius V gathered Catholic states into an allegiance known as the Holy League. The navy of the Holy League met forces from the Ottoman Empire, and, though they were outnumbered, famously defeated the Turks thanks to the intercession of Mary. This battle is memorialized in stained glass windows in the Basilica on campus (read why here), near the reliquary chapel that holds relics of Pope St. Pius V.

One other tradition from Pius’ reign remains. As a Dominican, Pius wore his community’s white habit and refused to change out of it when he was elected pope. His successors acknowledged and honored his holiness by wearing the same garb, which is why the pope is always clothed in white today.

Pope St. Pius V, your zeal and faithfulness guided the Church through the Counter-Reformation—pray for us!