In his place, his surviving relatives, namely his cousin Diego Cristóbal Túpac Amaru, continued the war, albeit using guerilla tactics, and transferred the rebellion's focal point to the Collao highlands around Lake Titicaca. Government efforts to destroy the rebellion were frustrated by, among other things, a high desertion rate, hostile locals, scorched-earth tactics, the onset of winter, and the region's altitude (most of the troops were from the lowlands and had trouble adjusting).[1] An army led by Diego Cristóbal occupied the strategically important city of Puno on May 7, 1781, and proceeded to use it as a base from which they launched attacks all across Upper Peru.[2] Cristóbal would hold the town and much of the surrounding territory until mounting losses and diminishing support convinced him to accept a general amnesty from Viceroy Agustín de Jáuregui. A preliminary treaty and prisoner exchange were conducted on December 12, and Cristóbal's forces formally surrendered on January 26, 1782.