Upon returning home from the Philippines, the three squadrons were sent to Fort Leavenworth, Fort Riley, and Jefferson Barracks respectively. In 1905, the troopers returned to the Philippines, when the Moro Rebellion began. This time, the troopers would operate in the southern Philippines on the islands of Mindanao and Jolo. Between 5-8 March 1906, the 4th Cavalry fought in the First Battle of Bud Dajo, where rebellious forces of the Islamic Sultanate of Sulu had fortified the Bud Dajo volcano. 211 dismounted troopers advanced up the sides of the steep volcano alongside other elements of the US Army and Philippine Constabulary. The going was tough and they had to slash through the jungle with machetes up a 60% slope. After reaching the enemy defensive positions, the troopers engaged in a gun battle, then charged, and the American bayonet clashed with the Filipino Kris. Nearly 1,000 Filipinos were killed, including civilians not engaged in the battle, and 21 Americans were killed and 70 were wounded. This was the bloodiest battle of the Moro Rebellion and it is depicted today at the top of the 4th Cavalry's Coat of Arms.