By the Treaties of Velasco made after Texans captured General Santa Ana after the Battle of San Jacinto, the southern border of Texas was placed at the "Rio Grande del Norte." The Texans claimed this placed the southern border at the modern Rio Grande. The Mexican government disputed this placement on two grounds: first, it rejected the idea of Texas independence; and second, it claimed that the Rio Grande in the treaty was actually the Nueces River, since the current Rio Grande has always been called "Rio Bravo" in Mexico. The latter claim belied the full name of the river in Mexico, however: "Rio Bravo del Norte." The ill-fated Texan Santa Fe Expedition of 1841 attempted to realize the claim to New Mexican territory east of the Rio Grande, but its members were captured by the Mexican Army and imprisoned. Reference to the Rio Grande boundary of Texas was omitted from the U.S. Congress's annexation resolution to help secure passage after the annexation treaty failed in the Senate. President Polk claimed the Rio Grande boundary, and when Mexico sent forces over the Rio Grande, this provoked a dispute. In July 1845, Polk sent General Zachary Taylor to Texas, and by October, Taylor commanded 3,500 Americans on the Nueces River, ready to take by force the disputed land. Polk wanted to protect the border and also coveted for the U.S. the continent clear to the Pacific Ocean.