The order grew out of the activity of Ignatius, a Spanish soldier who experienced a religious conversion during a period of convalescence from a wound received in battle. After a period of intense prayer, he composed the Spiritual Exercises, a guidebook to convert the heart and mind to a closer following of Jesus Christ. On August 15, 1534, in Paris, six young men who had met him at the University of Paris and made a retreat according to the Spiritual Exercises joined him in vows of poverty, chastity, and a pilgrimage to Jerusalem. If this last promise did not prove possible, as it did not, they vowed to accept any apostolic work requested by the pope. In 1539 Ignatius drafted the first outline of the order’s organization, which Pope Paul III approved on September 27, 1540.

The society introduced several innovations in the form of the religious life. Among these were the discontinuance of many medieval practices—such as regular penances or fasts obligatory on all, a common uniform, and the choral recitation of the liturgical office—in the interest of greater mobility and adaptability. Other innovations included a highly centralized form of authority with life tenure for the head of the order, probation lasting many years before final vows, gradation of members, and lack of a female branch. Particular emphasis was laid upon the virtue of obedience, including special obedience to the pope. Emphasis was also placed upon flexibility, a condition that allowed Jesuits to become involved in a great variety of ministries and missionary endeavors in all parts of the world.

The society grew rapidly, and it quickly assumed a prominent role in the Counter-Reformation defense and revival of Catholicism. Almost from the beginning, education and scholarship became the society’s principal work. The early Jesuits, however, also produced preachers and catechists who devoted themselves to the care of the young, the sick, prisoners, prostitutes, and soldiers; they also were often called upon to undertake the controversial task of confessor to many of the royal and ruling families of Europe. The society entered the foreign mission field within months of its founding as Ignatius sent St. Francis Xavier, his most gifted companion, and three others to the East. More Jesuits were to be involved in missionary work than in any other activity, save education. By the time of Ignatius’s death in 1556, about 1,000 Jesuits were working throughout Europe and in Asia, Africa, and the New World. By 1626 the number of Jesuits was 15,544, and in 1749 the total was 22,589.

Within 40 days of starting his studies, Xavier began to proselytise in a broken Japanese by explaining the Ten Commandments to a group of locals. While he never learned to read or write Japanese, he phonetically wrote what he heard using Roman letters, which is called Romaji today. Steadily improving his language skills, the priest would carry himself up to the local temples to debate with the monks that resided there, often being met with laughs at his tenuous grasp of Japanese. Not perturbed, he and his fellow Jesuit priests would stay up late into the night studying the intricate dialect.