The end of World War II (1945) made it possible to think about the universal expansion of Opus Dei, which had already begun, albeit in a limited way to Portugal and Italy. This expansion meant being subject to pontifical rather than diocesan authority, and so, in 1946 St Josemaria moved to Rome, settling there until his death. In 1947 and 1950 Pope Pius XII granted Opus Dei the canonical approvals permitting not only the expansion of Opus Dei but also the admittance of married people as members. Further, diocesan priests could also join the Priestly Society of the Holy Cross, while remaining united with their bishops. (In 1982, after St Josemaria’s death, Opus Dei was established by the Pope as a Personal Prelature, thus achieving full juridical configuration in keeping with the reality of its spirit and activity.)

During his years in Rome (1946-1975), St Josemaria stimulated and guided the expansion of Opus Dei throughout the world, using all his energies to give the faithful of Opus Dei, both men and women, a solid doctrinal, ascetic and apostolic formation. In 1946 members of Opus Dei began to work in Great Britain, Ireland and France, reaching most of the countries of Western Europe in successive years. In 1948 it began its work in Mexico and the United States and, soon afterwards, in a large number of Latin American countries. By the beginning of the 1960’s, Opus Dei established a stable presence in Asia and Africa: Japan, the Philippines and Kenya. Many educational, charitable and apostolic initiatives were started as well, such as the University of Navarre (Spain), of which St Josemaria was the first Grand Chancellor.

In 1948 and 1953 two centers of formation were established in Rome, one for men and another for women (the Roman College of the Holy Cross and the Roman College of Holy Mary, respectively). The Colleges made it possible for members of Opus Dei from diverse countries to study in Rome. Both Roman Colleges facilitated the direct and immediate contact of many of the first generations of Opus Dei members with St Josemaria.