Jonathan Maxson was the father of Arthur Maxson and the husband of Jessica Maxson. He and his wife died when their son was still very young, making Arthur the last of the Maxson dynasty in 2277.
Jonathan is a descendant of Roger Maxson, the founder of the Brotherhood of Steel, he was a high-ranking paladin just outside the New California Republic. He was, however, killed in battle.
Jonathan Maxson is mentioned only in Fallout 3.