The fourth pope during the period of the Reformation, Paul III became the first to take proactive reform measures in response to Protestantism. His reforms help shape Roman Catholicism for centuries thereafter, chiefly by bringing about a doctrinal response to Protestant theology. Born Alessandro Farnese on February 28, 1468, his family was prominent in the Italian political world and secured for him a humanist education in Rome, Florence, and Pisa. While in Florence, he learned in the court of the prominent Medici patriarch, Lorenzo the Magnificent, alongside two future Medici popes (Leo X and Paul’s own predecessor, Clement VII). He entered ecclesiastical service in 1492 as treasurer of the Roman church under then-pope Alexander VI and became cardinal deacon in 1493. Pope Julius II would name Paul bishop of Parma in 1509. He did not receive ordination until 1519, but collected numerous benefices while serving in Rome. The young Renaissance cleric lived a notably dissolute life, taking for himself a mistress and having three sons with her.

Paul’s life took a notable turn, however, around 1513. Already serving as bishop of Parma, he came under the influence of his vicar general, Bartolomeo Guidiccioni. This led to the future pope breaking off the relationship with his mistress and committing himself to reform in his Parma diocese. He began instituting the limited reform statutes decreed at the Fifth Lateran Council (1512–17). He had Guidiccioni administer the reforms in Parma and organize a reform synod there in 1519. Paul also undertook a visitation of the diocese himself in 1516. By the time of his ordination in 1519, he had emerged as a leading member of the reform wing in the Roma curia. When his papal predecessor, the similarly reform-minded Hadrian VI died in 1523, Paul was a candidate for the tiara but lost a contested election to Clement VII during a fifty-day conclave. The reforming cardinal was humiliated by the defeat and Clement subsequently marginalized his voice in the curia for the next eleven years. When he died, however, Paul was the oldest member of the curia and was quickly elected pope after a two-day conclave on October 13, 1534, under the assumption that he would aid in bringing about the long promised council and the reform of the church associated with it.

As pope, Paul balanced his newfound commitment to reform with the nepotism common among Italian popes of the Renaissance era. He notoriously appointed two teenage grandsons to significant positions in the Roman curia. He also sought to further the economic and political interests of the Farnese family within the Papal States, eventually giving Parma and Piacenza over to his son, Pierluigi. As a patron of the Renaissance arts, he continued the projects of his sixteenth-century predecessors. He supported Michelangelo’s completion of the Last Judgment in the Sistine Chapel, resumed the work on St. Peter’s, and promoted urban restoration in Rome to repair damage done during Charles V’s 1527 sack of the city. He also put the Vatican library under control of the humanist and future pope Marcello Cervini.

Nonetheless, Paul remained true to his intentions of reform. He announced at his election the plan to convoke the needed council. In the early years of his pontificate, he began filling the College of Cardinals with ecclesiastics committed to reforming the church. They included John Fisher, later to be executed by Henry VIII; Gian Pietro Carafa, the future Paul IV; Gasparo Contarini, a noted reformer; Jacobo Sadoleto, another famed humanist; Reginald Pole, who would later serve as papal legate to England during Mary’s restoration of Catholicism; and Cervini, the future Pope Marcellus II.  Several of these cardinals spearheaded a reform commission Paul appointed in 1536 to make proposals for the promised council. They produced the 1537 Consilium de emendenda ecclesia, which suggested broad reform of abuses in the church that had resulted from unrestrained papal authority. The document was leaked broadly, received a critical response from Luther, and ultimately was not put into practice, though it did influence many of the disciplinary reforms at Trent. During his pontificate, the pope oversaw several efforts to stem the tide of Protestantism and defend Catholic teachings. These included the institution of the Congregation of the Roman Inquisition in 1542, which primarily targeted suspected Protestant teachings in papal territories, and the start of many new religious orders that would further the cause of reform, such as his approval of the Jesuits in 1540. He also finally confirmed the excommunication of Henry VIII in 1538, which Clement had pronounced in 1534 but had been subsequently suspended.

While Paul had convoked a council first for Mantua in 1537, then for Vicenza in 1538, political tensions between the Empire and France and diplomatic efforts to resolve the religious controversies prevented it from convening. The Peace of Crépy between France and Charles V in 1544, however, finally paved the way for the opening of the Council of Trent on December 13, 1545. Charles had urged the council to address only questions of discipline and reform, but Paul pressed for doctrinal measures to be taken against Protestantism. In the sessions under his presidency (1545–47), Trent published decrees on original sin, the relationship between Scripture and tradition, the authority of the Latin Vulgate, and justification, though it promoted little in the way of practical reforms. These doctrinal positions were all direct responses to Protestant opinions and effectively signaled the start of the Counter-Reformation. Paul eventually proposed a transfer of the council to Bologna after an outbreak of illness caused a scare amongst the participants, but Charles would not allow it because it would have placed the council on papal soil. As a result, the pope suspended the council after the eighth session in 1547 and it did not convene again until 1553 under his successor, Julius III.

Conflict with Charles would mark the remainder of Paul’s pontificate. He had given the lands of Parma and Piacenza to his son and noted enemy of the emperor, Pierluigi, who was murdered in 1547 by an ally of Charles. Paul’s grandson, Ottavio, was recruited to join Charles, who gave him Pierligui’s land. This caused a rift in the Farnese family that would consume the pope the remainder of his tenure, though he finally reconciled with his son before death. Paul died of fever on November 10, 1549, and was buried in St. Peter’s.