In early 1564, Spanish governor Pedro de Villagra was taking measures to protect all the towns and forts he already held against the growing Mapuche revolt and to organize a field army in Concepcion. He knew that one of the Mapuche objectives was to surround Concepcion, and preparations were made to support a long siege. Raids by Mapuche bands had made it unsafe for Spaniards to go farther than a league from the city. After a brief fight, 3,000 Mapuche in the Itata River valley under Loble defeated the troops of captain Francisco de Vaca coming with reinforcements from Santiago. Meanwhile, another 3,000 warriors under Millalelmo defeated the troops coming from Angol under captain Juan Perez de Zurita, at a crossing of the Andalién River two leagues from Concepcion. Both defeats had reduced the garrison of Concepcion to defensive measures and cut off Concepcion from aid by land. The survivors of the two battles had to retreat to Santiago and were in no condition to break through the investment around Concepcion. Meanwhile, the caciques Millalelmu and Loble with 20,000 warriors from the area between the Itata and Bio-Bio rivers, had looted and destroyed Spanish estancias in the vicinity of Concepcion, took their herds, and then settled down to besiege Concepcion in early February 1564. The Mapuche entered the city, sacking and burning it, the population crowding within the walls of its fortress with its 200-man garrison under governor Pedro de Villagra. The Mapuche then built a fortified camp on heights overlooking the city from which they descended to attack it. The siege lasted two months with continuous skirmishes. At the end of March two Spanish ships arrived bringing food that permitted the population to continue to withstand the siege for a much longer time. On the other side the Mapuche had used up local sources of food, and without pack animals and transport vehicles were finding it difficult to bring in enough to maintain their large force. Also the harvest season was coming and failure to bring in the crops would result in a winter of hunger for their families. With the recent news of the defeat of the Mapuche toquiIllangulién at the Battle of Angol, they were also nervous that their undefended homes might be attacked from Angol or Santiago. On the first of April the Mapuche army raised the siege and dispersed to their homes for the winter.
