There he was promoted to general and confronted
Martin Miguel de Guemes, leader by the way he was carrying on the Guerra Gaucha, successful defensive strategy of defending northern border, but very expensive for the province, especially for high classes. In the mid-1817 he was named provincial commander of the army of
Cordoba in almost permanent struggle with small groups of rebels gauchos, no positive results against the feds.
Sierra Campaign In 1819 Arenales joined the
Army of the Andes in Chile. General
José de San Martín orders Arenales to command an expedition as part of the
Freedom Expedition of Peru, sending him to
Pisco, Peru on 5 October 1820, beginning the Sierra Expedition. After his arrival, at the destination, he took over the two major campaigns to the mountains. On 6 December 1820, Arenales led troops into the
Battle of Pasco (
es), using thick snowfall to launch a surprise attack. Arenales defeated the royalist troops commanded by
Diego O'Reilly, capturing O'Reilly and incorporating prisoners into his own forces. Upon news that royalist forces were defeated by Arenales' expedition, the city of
Huánuco called for a town meeting on 9 December 1820. Don Eduardo Lúcar y Torre, a colonel of the royalist army, allowed the citizens of Huánuco to vote on whether or not to join Arenales' cause, with the majority voting to join the patriot movement. On 15 December 1820, Huánuco declared independence and because of their assistance, Lúcar y Torre was named Mayor of Huánuco and José Figueroa was named the commander of arms. On 8 January 1821, Arenales regrouped with General San Martín. ==Governor of Salta==