By 1819, Santander was given command of the republican army's vanguard by Bolívar during the campaign to liberate New Granada. Santander was one of the battlefield commanders during the republican victory at the battle of "el Pantano de Vargas" (Battle of Vargas Swamp) and later at the Battle of Boyacá, on August 7 of that same year. After these battles, he was promoted to Commanding General, the equivalent of a modern major general.