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(1815-1872), born in New York, graduated at the U.S. Military Academy in 1839. He published "Elements of Military Art and Science" in 1846, which was a classic work at that time, and a treatise on "International Law." He was prominent in the military and political movements in California from 1846 to 1854, and in 1861 was appointed major-general of the U.S. army and assigned to the Department of Missouri, and successfully organized that district. In 1862 he received command of the Mississippi Department, and was soon after appointed commander-in-chief of the army, which position he retained until Grant was made lieutenant-general. After the war he commanded the Pacific Division until 1869, and the Division of the South from 1869 to 1872.