Philip St. George Cooke (June 13, 1809 – March 20, 1895) was a career United States Army cavalry officer who served as a Union General in the American Civil War. He is noted for his authorship of an Army cavalry manual, and is sometimes called the "Father of the U.S. Cavalry." Early life Cooke was born in Leesburg, Virginia, June 13, 1809. He graduated from the United States Military Academy in 1827 and was commissioned a brevet second lieutenant in the infantry. He served at a variety of installations in the American West and in the Black Hawk War. In 1833 he was promoted to first lieutenant in the newly formed 1st U.S. Dragoons. Cooke went on numerous trips of exploration into the Far West with the Dragoons. As Captain in command of 200 Dragoons, he disarmed and arrested Colonel Jacob Snively's Republic of Texas company of about 100 men, who were attempting to disrupt trade along the Santa Fe Trail, in what was described as the Second Texas Santa Fe Expedition. During the Mexican–American War he led the Mormon Battalion from Santa Fe to California, establishing what became known as Cooke's Wagon Road, later to become the southern route to California during the California Gold Rush. He received a brevet promotion to lieutenant colonel for his service in California. In command of 2nd U.S. Dragoons, he defeated the Jicarilla Apache in Ojo Caliente, New Mexico, in 1854, was in the 1855 Battle of Ash Hollow against the Sioux, and was sent to keep the peace in Bleeding Kansas in 1856–1857. Acquainted with Brigham Young, Cooke took part in the Utah expedition of 1857–1858, after which he was promoted to colonel and assigned command of the 2nd U.S. Dragoons. He was an observer for the U.S. Army in the Crimean War and commanded the Department of Utah from 1860 until 1861. The issue of secession deeply divided Cooke's family. Cooke himself remained loyal to the Union, but his son, John Rogers Cooke, became an infantry brigade commander in the Army of Northern Virginia. J. E. B. Stuart, the famous Confederate cavalry commander, was Cooke's son-in-law. Cooke and Stuart never spoke again, Stuart saying, "He will regret it only once, and that will be continually." Civil War At the start of the American Civil War, the U.S. Army had five mounted regiments. Cooke commanded the 2nd Dragoons, which was redesignated the