Complex sentence: On April 14,1865, Atzerodt rented room 126 at the Kirkwood, directly above the room where Johnson was staying; he arrived there at the appointed time and went to the bar downstairs, carrying on his person a gun and a knife.
Split into simpler sentences: On April 14,1865, Atzerodt rented room 126 at the Kirkwood, directly above the room where Johnson was staying. He arrived at the Kirkwood at the appointed time and went to the bar downstairs, carrying on his person a gun and a knife.