Spanish military forces played a significant role in events in Texas from 1519 with the first mapping of the Texas coast until 1821 when they relinquished duties to the forces of the newly independent Mexico. First contact between Europeans and American Indians living in Texas resulted from the various intentional and unintentional expeditions by the conquistadors who sought to identify the lands natural resources beginning in the 1520s. After initial exploration, little activity occurred in Texas until 1685 when French forces under René Robert Cavelier, Sieur de La Salle landed at Matagorda Bay and hoisted the French flag over Texas soil. The claim would be short-lived and Spanish forces controlled the area again by 1689. Once missions were established, duties included presidio building and operations as well as occasional punitive expeditions against Indians. During the American Revolution, cattle from Texas were trailed to Louisiana to support Spanish and Revolutionary forces at the request of Louisiana Governor Bernard de Gálvez.
By the early 1800s, Spanish forces began contending with maintaining Spain’s border with the United States and fending off various filibustering expeditions. During the Mexican War for Independence, the tasks would blur with subduing revolutionaries. In August of 1813, Spanish forces under General Joaquín de Arredondo soundly defeated revolutionaries at the Battle of Medina in the bloodiest battle fought on Texas soil with nearly 1,400 killed. Eight years later, responsibility for military affairs in Texas shifted to those of the United Mexican States (Mexico).