The 13th Cavalry Regiment was first constituted on 2 February 1901 in the Regular Army, and its first active component was K Troop. The Regiment was organized on 26 July 1901 at Fort Meade, South Dakota. Immediately following the American takeover of the Philippines after the Spanish–American War in 1898, Filipino leader Emilio Aguinaldo led a rebellion against American rule and the Philippine–American War erupted in 1899. By 1902, Aguinaldo had sworn allegiance to the United States and the war was officially declared to be over, but insurgents still plagued the countryside, prompting the deployment of the 13th Cavalry Regiment to the Philippine Islands. From 1903 to 1905 the 13th Cavalry conducted counter-insurgency operations against Filipino rebels and bandits until their return to the United States. In 1909 they returned to the Philippines and continued to conduct counter-insurgency operations until 1910.