John, the son of Zebedee, was called along with this brother James ("the Great") to be one of Jesus' twelve apostles who would accompany him on his ministry. John appears in the lists of apostles in the synoptic gospels as well as Acts. John and his brother James were given the nickname "Boanerges" (sons of thunder) by Jesus; some believe this was a reference to their tempers. Although younger than James, he appears to have first been a disciple of John the Baptist before following Jesus.
John has been an important figure for Christianity because he is believed to have been the author of the fourth (non-synoptic) gospel, three canonical letters, and the book of Revelations. Most scholars no longer attribute all (or any) of this to an original companion of Jesus, but that doesn't change John's stature for historical Christianity.
John, along with his brother James, is portrayed in the gospels as perhaps being more important than most of the other apostles. He was present at the resurrection of Jarius' daughter, at Jesus' transfiguration, and at the Garden of Gethsemane before Jesus was arrested. John is one of the first apostles to believe that Jesus had risen from the dead and one of the first to recognize him standing at the shore of Lake Genesareth.
Paul later describes John as a "pillar" of the Jerusalem church. Other than a few references to him in the New Testament, however, we have no information about who he was or what he did. Tradition has it that Polycarp, one of the earliest church fathers and a bishop of Smyrna, as personally trained by John. This story is used to advance the idea that there was a direction connection between early church leaders, the apostles, and therefore Jesus himself.
Christian legend says that he moved to Ephesus with the Virgin Mary and both died there from old age, which would make him one of the few apostles not believed to have been martyred for his faith. Mormons teach that John never really died at all but is instead waiting for Jesus' Second Coming.
Read More: Saint John the Apostle