John the Evangelist was thought to be not only the youngest of the Apostles but the longest-lived, dying peacefully of natural causes at an advanced age. Although he escaped actual martyrdom, St. John endured considerable persecution and suffering for his beliefs. He is said to have drunk poison to prove his faith, been cast into a cauldron of boiling oil, and at one point banished to the Greek island of Patmos. He remained miraculously unharmed throughout these trials and returned to Ephesus, where it is believed he wrote the Gospel according to John.
Source: The Free Dictionary