The Church is apostolic because she is founded on the apostles, in three ways: - she was and remains built on "the foundation of the Apostles," 362 The witnesses chosen and sent on mission by Christ himself; 363 - with the help of the Spirit dwelling in her, the Church keeps and hands on the teaching, 364 The "good deposit," the salutary words she has heard from the apostles; 365 - she continues to be taught, sanctified, and guided by the apostles until Christ's return, through their successors in pastoral office: the college of bishops, "assisted by priests, in union with the successor of Peter, the Church's supreme pastor": 366

Neighboring particular Churches who share the same culture form ecclesiastical provinces or larger groupings called patriarchates or regions. 413 The bishops of these groupings can meet in synods or provincial councils. "In a like fashion, the episcopal conferences at the present time are in a position to contribute in many and fruitful ways to the concrete realization of the collegiate spirit." 414