18 Indeed, in considering all the elements pertaining not only to the right intellectual and spiritual formation of the students for the priesthood but also the needs and to the special mentality and emotional make-up of their own people, this Apostolic See has always recommended, both to the foreign and to the local clergy, that they should study the discipline of missiology. Our predecessor Benedict XV established chairs of this discipline in the Pontifical Urban Athenaeum of the Propagation of the Faith; (33) and Our immediate predecessor, Pius XII, remarked with satisfaction on the founding of the Institute of Missiology in the same university; "not a few faculties and chairs of missiology," he said, "have been established in Rome and in other places." (34) Therefore, in the curricula of the seminaries of mission countries, there will be no lack of studies pertaining to the various missiological disciplines, nor of technical training in all the practical skills which are considered useful for the future work of the clergy in those countries. Therefore it is absolutely necessary that their training not only conform to the best ecclesiastical traditions of a solid and undiluted education, but also that it open up and sharpen the minds of the seminarians in such a way as to enable each individual to evaluate correctly his own and his country's particular kind of culture, especially as it pertains to philosophical and theological teachings and their relation to the Christian religion.
Source: Princeps Pastorum (Vatican.va)