 He then returned to Buenos Aires and took part in the siege of Montevideo.Güemes returned to Salta in 1815, and organized the resistance against the royalists (forces loyal to Spain) employing local gauchos trained in guerrilla tactics.He was appointed Governor of Salta Province and in November of that year, General José Rondeau, appointed leader of the Peru campaign to replace José de San Martín, suffered a defeat and attempted to take weapons from Salta's gauchos.