The term Apostle is derived from the New Testament Greek word ἀπόστολος or apostolos, meaning one who is sent forth as a messenger and should not be confused with a disciple(who is a follower or a student who learns from a “teacher”). Traditionally, Jesus is said to have had Twelve Apostles who spread the Gospel after his Crucifixion.
Paul of Tarsus also claimed the title of Apostle to the Gentiles, even though other apostles actively recruited Gentiles and Peter’s role was never restricted to just Apostle to the Jews , indeed traditionally the first gentile convert is considered to be Cornelius the Centurion, who was recruited by Peter. Paul claimed a special commission from the risen Jesus, separate from the Great Commission given to the Twelve. Paul’s mentor Barnabas is also termed an apostle. Paul did not restrict the term apostle to the Twelve, either because he didn’t know it or resisted it.This restricted usage appears in Revelation. In modern usage, major missionaries are sometimes termed apostles, as in Saint Patrick, Apostle of Ireland.
The period of Early Christianity during the lifetimes of the apostles is called the Apostolic Age. In the second century, association with the apostles was esteemed as evidence of authority and orthodoxy. Paul’s epistles were accepted as scripture (see Development of the New Testament canon), and two of the four gospels were associated with apostles, as were other New Testament works. Various Christian texts, such as the Didache and the Apostolic Constitutions, were attributed to the Twelve Apostles. Bishops traced their lines of succession back to individualapostles, who were said to have established churches across great territories. Christian bishops have traditionally claimed authority deriving, by apostolic succession, from the Twelve. Early church fathers came to be associated with apostles, such as Pope Clement I with Peter the Apostle. The Apostles’ Creed, popular in the West, was said to have been composed by the apostles themselves.
The 12 Apostles of Christ 