When John joined his brother, James, and they traveled with John the Baptist, he was the youngest disciple. John and James were part of Jesus' ministry for three years, and then they were instrumental in forming the early church. Long after Jerusalem was destroyed, John wrote Revelation while exiled on Patmos. Eventually, Nerva, the Roman Emperor, freed John and he was taken to Ephesus. During his last years, he taught, preached and wrote about his travels with Jesus. He was the last of Jesus' original twelve disciples to die.