Harry Truman was vice president for 82 days when FDR died on April 12, 1945, making Truman president. Most of America had never heard of the former haberdasher from Missouri. The vice presidency was an obscure post in those days, not worth the proverbial bucket of warm spit. But Truman was no shrinking violet. He'd chaired a senate committee investigating corruption in the defense industry, and had done this while the war was going on, something modern-day patriots would probably call unpatriotic. Truman is the only president who ever dropped the big one. He also uttered the famous line "the buck stops here." Truman anecdotes appear on pages 141, 223, 233, 265 and 281 in A Book of Ages.
Jesus is a difficult figure to pin down in terms of age. He was a minor figure when he died and entirely obscure when he was born, so his dates are rough estimates and vary significantly. Rather than going with the religious accounts I chose the dates arrived at by historians, dates attached to contemporaneous events, but the stories are the ones we know from the New Testament. His remarkable bible knowledge at a young age, the anti-establishment, anti-authoritarian, explicitly liberal sermons, the warnings about what's in store for rich people after they die, the betrayal and his followers' memoirs. Jesus wasn't a shrinking violet either, which makes for good stories. He appears on pages 1, 26,120 and 126 in A Book of Ages.