William "Bull" Nelson (September 27, 1824 – September 29, 1862) was a United States naval officer who became a Union general during the American Civil War. As a Kentuckian, Nelson could have sympathized with the Confederates but, like his state, he remained loyal to the United States of America. Secretary of Treasury Salmon P. Chase believed Nelson's actions had kept Kentucky loyal and promoted him to brigadier general in September 1861. Nelson's 4th Division bore the brunt of heavy fighting at the Battle of Shiloh and took part in the Siege of Corinth; he was the first man to enter the town. Wounded at the Battle of Richmond, Nelson was forced to retreat to Louisville to plan a new assault. It was there that General Jefferson C. Davis, still officially on sick leave, reported to Nelson, who was dissatisfied with his performance and insulted him in front of witnesses. A few days later, Davis demanded a public apology, however, the situation rapidly escalated into a physical confrontation, which concluded in Davis mortally wounding Nelson with a pistol. Early life William "Bull" Nelson was the third and youngest son of Dr. Thomas W. Nelson (1796–1849) and Frances Doniphan (1795–1845) of Maysville, Kentucky. He attended Maysville Academy (Seminary) and was enrolled in Norwich University at 13. Two years later, Nelson's preparatory training at the Vermont military school concluded when Representative Garrett Davis secured an appointment for him to become a midshipman in the US Navy. In the spring of 1840, Nelson reported for training aboard the . For the next five years, he sailed the South Pacific. Nelson then joined the first class to attend the newly established Naval Academy, at Annapolis, Maryland. On July 11, 1846 Nelson became a passed midshipman, and the next October, he reported for duty aboard the , the flagship for the Home Squadron in the Gulf of Mexico. At the Siege of Veracruz, he served with Naval Battery No. 5, and on the second Tabasco Expedition, Nelson was a member of the Second Artillery Division. In February 1848, he became acting master of the . At the conclusion of his service, Nelson received a sword for heroism and proficiency as an artillerist. In the summer of 1849, he joined the Mediterranean Squadron, and on September 1, 1851, he was acting lieutenant of the when exiled Hungarian revolutionary Louis Kossuth boarded the vessel to come to the