Since the fall of 1864 John Wilkes Booth along with others had been plotting against Lincoln. A supporter of the Confederacy, Booth was also a popular actor, a son of the great actor Junius Brutus Booth who had written a letter, perhaps tongue in cheek, to Andrew Jackson, threatening to assassinate him. His brother Edwin Booth, perhaps the foremost American actor of his day and who had saved the life of Robert Todd Lincoln, was a firm supporter of Lincoln and the Union, and had banned his brother from his house in New York. Booth had an unexplained trip to Montreal in 1864. It is tempting to suspect that he got in contact with Confederate intelligence operatives active in Canada, but no evidence has been found linking Booth to Confederate intelligence then or later.
Initially Booth and his co-conspirators had planned to kidnap Lincoln and smuggle him South and trade him for Confederate prisoners of war. They gathered on March 17, 1865 to do so when Lincoln was en route to a play but Lincoln unknowingly foiled the plot by changing his plans. Booth and his band awaited another opportunity.