The sentiments of the assembled chiefs in respect to the farther prosecution of the war, were various and discordant. Colocolo and most of the Ulmens were of opinion, that they ought in the first place to endeavour to free their country from the remaining Spanish establishments within its bounds, before attempting to carry their incursions to the north of the Biobio. Tucapel and some others of the most daring officers, insisted that they ought to take advantage of the present circumstances to attack the Spaniards even in the city of St Jago, the centre of their colonies, while in a state of consternation and dismay, and to drive them entirely from the whole kingdom of Chili. Caupolican applauded the heroic sentiments of Tucapel, yet adopted the council of the elder chiefs, as the most prudent and beneficial for the interests of the nation.
About this time Lincoyan, the former toqui, who was at the head of a detached body of troops engaged in harassing the dispersed settlements of the Spaniards in Araucania, fell in with a party of fifteen Spaniards, on their march from Imperial to join Valdivia, of whose total defeat they had not yet received intelligence. Before engaging with the enemy, whom they confidently expected to defeat with the utmost facility, these Spaniards vainly regretted that their number exceeded twelve, in hope that the event of the day would stamp upon their names the chivalrous title of the twelve of fame. Their wishes were soon more than gratified, as seven of them fell at the first encounter with the enemy, and the remaining seven, taking advantage of the swiftness of their horses, escaped severely wounded to the fortress of Puren, carrying with them the melancholy intelligence of the total destruction of Valdivia and his army. On this distressing news the Spanish inhabitants of Puren, and Frontera or Angol, retired to Imperial, where they considered themselves in greater security than in these other more inland fortresses, which were entirely surrounded by the country of the victorious enemy. About the same time the inhabitants of Villarica abandoned that settlement and took refuge in Valdivia; so that two Spanish establishments only now remained in the Araucanian country, and both of them at a great distance from reinforcements or assistance. As Caupolican determined upon besieging these two cities, he committed to Lautaro the charge of defending the northern frontier against invasion, and set out for the south to reduce the cities of Imperial and Valdivia.
The young and gallant vice-toqui, Lautaro, accordingly took post on the lofty mountain of Mariguenu, which intervenes between Conception and Arauco, and which he fortified with extraordinary care, rightly judging that the Spaniards would take that road in search of Caupolican on purpose to revenge the defeat and death of their general Valdivia. This mountain, which has proved fatal to the Spaniards on several occasions in their wars with the Araucanians, has a large plain on its summit interspersed with shady trees. Its steep sides are full of rude precipices and deep clefts or ravines, its western end being rendered inaccessible by the sea, while on the east it is secured by an impenetrable forest. The north side only was accessible to the Spaniards, and even in that way it was only possible to reach the top by a narrow and winding path.