Abraham Lincoln’s only surviving son, Robert Todd, fell on the train tracks in Jersey City in 1863.
He was pulled up to safety by John Wilkes Booth’s older brother, Edwin.
Edwin was known as one of the world’s greatest Shakespearean actors, and was the son of Junius Brutus Booth, another famous actor in his day (and an alcoholic). A statue is dedicated to him in Gramercy Park, NYC.
Robert Todd Lincoln was present at two other Presidential assassinations, but was asleep in bed the night his father was shot by John Wilkes Booth. He was present for Garfield’s assassination at the Sixth Street Train Station in Washington, D.C. by Charles J. Guiteau on July 2, 1881, at McKinley’s assassination at the Pan-American Exposition in Buffalo, New York where the President was shot by Leon F. Czolgosz on September 6, 1901.
The night President Lincoln was murdered at Ford’s Theater, he and Mary Todd were accompanied by Henry Rathbone, a military officer, and his new fiancée, Clara Harris. When Booth shot Lincoln, Rathbone made an attempt to stop his fleeing, but failed. He was stabbed several times by Booth before he jumped from the box to the stage and made his escape, despite a broken leg.
For years, Rathbone was haunted by –and in some circles, blamed for– Booth’s escape and resulting two week attempt at hiding. He recovered from his wounds, married Harris, and they had three children. He never mentally recovered, though, and in 1883 murdered his wife, and attempted to murder his three children as well. He was institutionalized and died in 1911.
His son, Henry Riggs Rathbone, went on to become a Republican Congressman from Illinois, Lincoln’s home state.
This information is readily available via Wiki, etc. but I’ve just put it all together after reading Sarah Vowell’s Assassination Vacation.