St. Robert Bellarmine, S.J. (1542-1621) was the chief Catholic theologian during the latter part of the sixteenth century and at the beginning of the seventeenth century. His literary production was immense, since he produced books and treatises on most areas of theology, including Scripture, Christology, Sacraments, Liturgy, Ecclesiology and Eschatology. Among his major works are the three Controversies contained in this series. Volume III is centered on the Sovereign Pontiff, the Bishop of Rome. First of all he proves the primacy of Peter among the twelve Apostles, and that Peter and his successors are the Vicar of Christ and as such, by the will and power of Christ, govern the whole Church.

They are the ultimate teachers of the faith; they are the ones who decide what the true faith is when there are disagreements or debates about such issues. Saint Robert also argues for the infallibility of the Pope in defining matters of faith and morals. And on this matter he was a key theological source at Vatican Council I when the infallibility of the Pope was solemnly defined as an article of faith for Catholics. According to Bellarmine, the Sovereign Pontiff has supreme power over spiritual matters in the Church. In all three Controversies he is refuting the errors of many adversaries of the Catholic Church. His favorite targets are Martin Luther and John Calvin. Robert Cardinal Bellarmine was greatly admired by bishops and Catholic theologians during his lifetime and was famous for his scholarship and preaching. He was the theologian and counselor for several Popes.

He was called another Augustine, another Athanasius. He was greatly detested by Protestants because of the power of his arguments to prove that they were in error.