During these years many expeditions were made to America and Africa. The Congregation was fully missionary. Another mission field was expanding, which we have called the missions ad gentes. Propaganda Fide assigned the Congregation the missionary task of Baja California (Mexico) and the territories of Rio de Oro, in Africa. Although there were many foundations, there were even more plentiful offers which were received but had to be refused: the Prefecture of Arauca, the Apostolic Vicariate of Para (Brazil), the Islands of Providencia and of San Andres, etc. All these expansions were due to the huge emphasis Fr. Xifre gave, especially to the foundation of Seminaries in Spain, which continued to function at full capacity. With the division of Provinces and the consequent distribution of the seminarians into smaller formation centers, numbers decreased, but this did not slow down the increasingly accelerated rhythm of the steady and vigorous expansion of the Institute through so many countries. The next two successors of Fr. Xifre maintained this emphasis.

Santo Domingo de la Calzada (La Rioja, Spain). He graduated in utroque jure from the Pontifical Lateran University of Rome in 1954, with the qualification of summa cum laude. In 1955 he obtained the title of Rotal Advocate. He taught at the Pontifical Lateran University and other Roman centers such as the Institute Regina Mundi and the Urbaniana University. His recognized competence made him worthy of the appointment to high curial positions in the Tribunal of the Apostolic Signatura and in the Pontifical Council for Legislative Texts, as well as for the position of Dean of the Faculty of Law of the Lateran University, etc. He collaborated in multiple magazines such as Commentarium pro religiosis of which he was secretary, Apollinaris and Monitor Ecclesiasticus. Among his publications are his Leges Ecclesiae post Codicem Iuris Canonici and Index verborum cum documentis Conciliae Vaticani Secundi. The Lord called the illustrious canonist to his Kingdom in Santa Pola, Alicante, this day of 1989.