The Peacemaker was also the nickname for an experimental 14" gun. In 1844, the ten ton cannon was the largest naval gun in the world, and was mounted on the first propellor-driven warship, the USS Princeton. On February 28th of that year, the Princeton was on a cruise on the Potomac loaded with dignitaries including President John Tyler. The gun was being fired to entertain the guests when it exploded, killing six people. Among the casualties were the Secretary of State and the Secretary of the Navy.