He broke his leg
According to history, Presidential Assassin John Wilkes Booth broke his leg as he jumped from the President's Box to the stage, claiming Booth's spur became entangled in the red, white, and blue flag that draped the front of the area where the Lincoln party sat. In the twenty-first century, however, historiography must compete with forensic history. A closer examination of primary sources, including letters from both Booth and the doctor who treated him, has increased the possibility of casting doubt on when Booth broke his leg: when he landed on the stage at Ford's Theatre, or later that evening as he raced away from the scene of the crime?
When he leapt from the Presidential Box to the stage, Booth claimed that he "broke my leg in jumping." Did he, however? Booth's claim also contradicted what eyewitnesses saw. A.M.S. Crawford, the first witness, was also seated in the Dress Circle section of the theatre. Crawford stated that "I saw him (Booth) as he ran across the stage" on the night of the assassination. Actor Harry Hawk, who was on stage at the time Booth jumped, saw Booth "rushing toward him with a dagger" in his hand. Other people in the theatre claim to have seen Booth run, not limp, across the stage that night. William Withers, Sheldon P. McIntyre, John Downing Jr., Dr. Charles Sabin Taft, Major General B.F. Butler, and Samuel Koontz were among the witnesses. According to these witnesses, John Wilkes Booth fled the theatre after landing on the stage. None of them described Booth limping or appearing to be in any pain.