Eldest son of empresario Martin de Leon. Came with parents from interior of Mexico to Texas, the northermost province, about 1800. Worked with his father in founding De Leon Colony and city of Victoria in 1820s. He was a commissioner of the colony and an Indian fighter. Loyal to cause of Texas freedom from Mexico, he was imprisoned by the Mexicans in Texas War for Independence. A cattleman and horseman, he owned the famous "Escondida" Ranch.