Alexander Slidell Mackenzie (April 6, 1803 – September 13, 1848), born Alexander Slidell, was a United States Navy officer, famous for his 1842 decision to execute three suspected mutineers aboard a ship under his command in the Somers Mutiny. Mackenzie was also an accomplished man of letters, producing several volumes of travel writing and biographies of early important US naval figures, some of whom he knew personally. Mackenzie was the brother of Senator John Slidell of Louisiana, who was later involved in the American Civil War's Trent Affair. Mackenzie was the captain of USS Somers when it became the only US Navy ship to undergo a mutiny, which led to executions, including Philip Spencer, the 19-year-old son of the Secretary of War John C. Spencer. Mackenzie's handling of the Somers Mutiny, including its lack of a lawful court martial, was highly controversial and public opinion ran against him. The mutiny proved the need for systematic training of cadets before they went to sea. In 1845, Secretary of the Navy George Bancroft seized on the Somers affair as a reason to establish the United States Naval Academy. Early life Mackenzie (then Slidell) was born April 6, 1803, in New York City, to Margery (also spelled Marjorie) ( Mackenzie) and John Slidell. Alexander was one of a large family of children. His older siblings included: Thomas Slidell, chief justice of Louisiana's state Supreme court; John Slidell, US Senator from Louisiana; and Jane Slidell, who married Commodore Matthew C. Perry. Jane's marriage to Perry was to have a particularly profound influence on her younger brother's life, bringing him into close contact with one of the nation's leading naval families, which included Matthew's heroic older brother, Commodore Oliver Hazard Perry, and members of Commodore John Rodgers' family, with whom the Perrys intermarried. In 1837–1838, Alexander Slidell petitioned the New York State legislature and obtained the right to change his name to Mackenzie, reputedly as a condition of claiming the inheritance of a maternal uncle. Naval service Mackenzie entered the U.S. Navy as a midshipman in 1815. A contemporary of Henry Wadsworth Longfellow and a personal friend of Washington Irving, he published a number of books, including A Year in Spain, Life of John Paul Jones, Life of Commodore Stephen Decatur, and Life of Commodore Oliver Hazard Perry (his late brother-in-law). He was promoted to lieutenant on January 13, 1825, and to commander on September