Born in Nijmegen, Netherlands, on Mary 8, 1521, Peter Canisius, began studies at the University of Cologne when he was fifteen years old, and received his masters' degree four years later. Shortly after completing his studies, he met Peter Faber who, in 1543, guided him through the Spiritual Exercises.
Canisius entered the Society of Jesus a month after finishing the Exercises. On June 12, 1546, Canisius was ordained a priest in Cologne, and began teaching Sacred Scripture; that same year he published new editions of the works of Cyril of Alexandra and Leo the Great. The following year he served as theologian to Cardinal Otto Truchess at the Council of Trent. In 1547, he met Ignatius in Rome, and was assigned to the first Jesuit school, that of Messina, Sicily.
In 1549, Pope Paul II asked Peter to return to Germany and help stop the defection of Catholics to Protestantism. For three years, Canisius and his companions worked at the University of Ingolstadt and succeeded in bring many people there back to Catholicism. Then, in 1552, Canisius was sent to Vienna to establish a seminary next to the Jesuits' college. During his three years in Austria, Canisius was court preacher and interim administrator of the diocese of Vienna. In these same years, he published The Summary of Christian Doctrine, a catechism for college students that had innumerable printings well into the 19th century.
Canisius' next assignment was that of provincial of Germany (1555-1569). This Jesuit province, that included Swabia, Bavaria, Bohemia, Austria and Hungary, allowed Canisius to have a wide influence in Counter-Reformation Germany. He often represented the Catholic position in gatherings with Protestants, particularly in Regensburg and Worms. In 1562, he was a theological expert at the Council of Trent, and he labored directly for the implementation of its decrees. He published several catechisms as well as books of meditations on the Gospels read during the liturgical year. Opus Marianum, which he authored in 1577, was the first book on Mary written by a Jesuit.
After his term as Provincial, Canisius was sent to Fribourg, Switzerland. There he opened Saint Michael's College in 1580, and preached for almost a decade. In 1591, he suffered a debilitating stroke, complicated by dropsy, lung problems and throat ulcers.
Peter Canisius died on December 21, 1597, having been active in the founding of eighteen colleges in Germany, Austria, Hungary and Poland, written thirty-seven books, and been a major contributor to the restoration of Catholicism in Germany and Austria.
Peter Canisius was beatified by Pope Pius XI in 1864, canonized by the same Pope on May 21, 1924, and declared a doctor of the Church on May 1, 1925.