On April 21, 1836, the independence of the Republic of Texas was secured by a decisive victory over the Mexican Army at the Battle of San Jacinto. Texas claimed the Rio Grande as its southern border but had sufficient military power to control only land north of the Nueces River. Although Antonio López de Santa Anna, the ruler of Mexico, signed the Treaties of Velasco ceding Texas territory from Mexican control, the treaty was never ratified by the Mexican Government. Santa Anna repudiated the treaty once he was released from Texan custody.