Martín De León, the only Mexican empresario to found a colony in Texas, was born in 1765 in Burgos, Nuevo Santander (now Tamaulipas), where his parents, Bernardo and María Galván De León, settled after moving from Burgos, Spain. The De Leóns were an aristocratic family of great wealth; members were educated in Madrid, Paris, and London and were acquainted with European rulers. Martín, however, declined his father's offer to complete his education in Monterrey and Europe, choosing instead to become a merchant and supplier of provisions to the miners of Real de San Nicolás. In 1790 he joined the Fieles de Burgos regiment, organized by Mexican viceroy Juan Vicente Guernes Pacheco as a defense against Indians in Nuevo Santander. De León was promoted to captain, thus achieving the highest rank available to a criollo. In 1795 he married Patricia de la Garza, daughter of Gen. Felipe de la Garza, commandant of the Eastern Internal Provinces. The couple settled in Cruillas, Nuevo Santander (now Tamaulipas), where they began ranching. An excursion to La Bahía, San Antonio, and Nacogdoches in 1805 induced De León to settle in Texas. He established a ranch between Chiltipin Creek and the Aransas River, stocked it with cattle, horses, mules, and goats that he brought from Mexico, and enclosed several leagues of land with a brush fence in an effort to corral and domesticate mustangs.
