The 1st Cavalry Regiment returned to the Philippines in 1908 and garrisoned Fort Stotsenburg for two years. This deployment was much quieter than their last one, and the regiment returned home on 12 February 1910. A, B, D, and K Troops were stationed at the Presidio of San Francisco and later joined the rest of their regiment at the Presidio of Monterey until 1 August 1914. Moving to Southern California, the 1st Cavalry garrisoned San Ysidro in response to growing tensions south of the border in Mexico. On 24 August 1915, the regiment moved to Calexico, California to strengthen the border and defend against raids by the "bandito", Pancho Villa. They remained guarding the border while General Pershing launched the Punitive Expedition and were still there when the US entered World War I. The 1st Cavalry did not participate in the First World War, but it remained guarding the border until 19 January 1923, when they went to Fort D. A. Russell, Texas. This was their last posting as horse cavalry, and during a parade on 14 December 1932, the troopers dismounted and passed in review, saluting their horses as they left them to become a mechanized unit. Moving to Fort Knox, Kentucky, the 1st Cavalry Regiment became the first mechanized unit in the United States Army, and was brigaded with the 13th Cavalry Regiment to form the 7th Cavalry Brigade (Mecz). In the summer of 1939, 7th Cavalry Brigade (Mecz) took part in the Plattsburgh Maneuvers and helped develop the Army's first tactics for mechanized warfare. In the summer of 1940, the Louisiana Maneuvers convinced the Army of the need to form an armored force and the 1st Armored Division was founded on 15 July 1940. The 1st Cavalry Regiment was redesignated the 1st Armored Regiment that same day, and was assigned to the 1st Armored Brigade. It wouldn't be long until America's fledgling armored force would be tested in battle.