John the Revelator or the John the Apostle or otherwise known as John of Patmos , he transcribed the Prophecy and Visions he received from an angel sent to him through an angel by Christ. John had been exiled to and was on the Island of Patmos. According to this page on “The Amazing Bible Timeline Page With World History” site, it is believed John was born around 6 A.D. and that he died around 100 A.D. Most accounts I have heard are unsure the year in which John was exiled. John was exiled by The Emperor(Roman Emperor) Dominitian.
I assume John was not killed on account of his age. The site mentioned in the paragraph above states the conditions of Patmos were very harsh. The last picture below shows that still to be true. There were mines on the island and it looks like not much else.