On February 21, 1862, a bloody Civil War battle was fought near Cortadero Mesa across the Rio Grande below the small village of Valverde, where Confederate forces led by Colonel Henry Hopkins Sibley clashed with Colonel E.R.S. Canby's Union troops posted at Fort Craig. Fighting in the arroyos and gullies of a dry riverbed physically cut regiments on both sides off from one another and often left them unable to communicate with their leaders. Communication and trust among Union troops were also hampered by the language barrier between Anglo regulars and New Mexico Hispanic volunteers. Control of the battlefield shifted back and forth between North and South, but the engagement ended in a Confederate tactical victory. The next day, however, when Sibley demanded the surrender of Fort Craig and its supplies, Canby adamantly refused, leaving the Confederates in a difficult position because they lacked enough food and military supplies either to launch a direct attack on the fort or to return to Texas. After spending several days burying their dead and transporting the wounded to Socorro, the Confederates pressed northward to Glorieta Pass near Santa Fe, where during a two-day battle in late March Union troops destroyed their remaining supply wagons. Unable to obtain reinforcements and supplies and without enough ammunition for a full day's fight, Sibley's column retreated south on a difficult route behind the San Mateo Mountains to the west, ending the Confederate plan to capture the gold fields of Colorado and the ports of California.