The first Lincoln to be connected to the four presidential assassinations was of course A. Lincoln himself. Honest Abe was shot in Ford's Theater by John Wilkes Booth on April 14, 1865 and died some hours later on the 15th.
The eldest son of Abraham Lincoln was Robert Todd Lincoln. Although he was in Washington, D.C. at the time, Robert was not present at his father's assassination. However, in 1881, Robert Lincoln was serving as President Garfield’s Secretary of War. Garfield invited Lincoln to accompany him on a trip and Lincoln was with Garfield at the train station in Washington on July 2, 1881, when Garfield was assassinated.
Some 20 years later, President McKinley invited Robert Lincoln to attend the Pan-American Exposition in Buffalo, New York with him. While there, on September 6, 1901, McKinley was assassinated. Robert Lincoln thereafter declined subsequent presidential invitations. Robert Lincoln’s last public appearance was the dedication of his father’s memorial in Washington on May 30, 1922. Although two Presidents — William Howard Taft and Warren G. Harding — were present, both of them managed to avoid being assassinated.
The year after JFK's assassination, lists of "spooky" coincidences between Lincoln and Kennedy started to appear in the media. For example, both presidents were elected to the House of Representatives in '46; both presidents were elected to the presidency in '60 and both presidents had vice-presidents named Johnson who took office upon their deaths.
It was also said that Lincoln had a secretary named Kennedy who warned him not to go to the theatre. While there is no official record showing that Lincoln ever had a secretary named Kennedy, Lincoln's bodyguard, William Crook, did in fact advise Lincoln not to go to Ford's Theater that night.
But the other part of that urban legend is true: Kennedy had a secretary, Evelyn Lincoln, who had warned him not to go to Dallas that fateful trip.