levies were the vanguard of the Patriot army advancing on Salta, and in consequence lost much valuable time waiting for reinforcements.
In March the Royalist vanguard advanced from Salta into the valley of Lerma, in search of supplies, under the command of Colonel Saturnino Castro, a native of Salta, who had the repute of being the first cavalry officer of the Royalist army of Peru, and whose valour had decided the day at Vilcapugio. The guerillas, who became known to history as the Gauchos of Salta, greatly harassed the progress of the expedition, swarming in the woods along the line of march, cutting off stragglers, driving in small detachments, and firing upon the main body from any convenient shelter.
On the 24th, videttes on the Guachipas River at the end of the valley, descried fifty-six of the enemy, under Captain Fajardo, approaching them. Captain Saravia collected thirty men armed with short muskets, and a group of peasantry with clubs and pikes, charged upon them and completely routed them, killing eleven including the captain, and making twenty-seven prisoners, while he had only three men killed and one wounded.
Meantime Güemes had entered the Sierra to the east of Salta, and on the 9th and 18th, two parties of his Gauchos surprised two detachments of the enemy. On the 29th he came so close to the city that Castro sallied out against him for about a league with eighty men, but was completely routed, with the loss of half his force.
For this feat Güemes was named Commandant-General of the Vanguard, and on the recommendation of San Martin, was raised to the rank of Lieutenant-Colonel.
Güemes then occupied the approaches to the city and harassed the garrison by daily attacks upon the suburbs. Being reinforced from Jujui, the Royalists then organised two expeditions of 500 men each. One, composed of a battalion of infantry and a squadron of light horse under Colonel Alvarez, marched early in June into the
