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.

The two Promaucians who alone had escaped from the fatal battle of Tucapel, by favour of the darkness and under covert of a thick wood, reached Conception, which they filled with grief and consternation, by relating the total overthrow and massacre of the army of Valdivia. When the general terror and dismay had a little subsided, the magistrates proceeded to open the sealed instructions which had been left with them by Valdivia, when he departed on his late fatal expedition. In these he named Alderte, Aguirre, and Villagran successively to the vacant government in case of his own decease. Alderte being gone to Europe, and Aguirre absent on his expedition into the distant province of Cujo, the command devolved on Villagran. After such preparations as appeared necessary under the present emergency, Villagran crossed the Biobio with a considerable army of Spaniards and Promaucian auxiliaries, intending to march for Arauco in the first place. In a narrow pass at no great distance to the south of the Biobio, he was vigorously opposed by a body of Araucanian warriors, who withstood the utmost efforts of his army for three hours, and then withdrew continually fighting, towards the top of the mountain where Lautaro awaited the approach of the Spaniards with the main body of his army, in a well chosen post defended by a strong palisade. Villagran ordered the squadrons of cavalry to force their way up the difficult passage of the mountain, which they effected with infinite difficulty and severe fatigue, and were received at a short distance from the summit by showers of stones, arrows, and other missiles, which were incessantly discharged against them by the vigilant and brave Araucanians. Villagran, who followed his cavalry at the head of all the infantry of his army, with six pieces of artillery, seeing the determined opposition of the enemy, several detachments of whom were endeavouring to gain his flanks and rear, ordered his musquetry to advance, and the artillery to take a favourable position for annoying the enemy.

The mountain was enveloped in smoke, and resounded on all sides with the thunder of the Spanish cannon and musquets, while the balls were heard whistling in every direction, and dealing destruction among the ranks of the valiant Araucanians, who continued vigorously to defend their post, undismayed at the numbers who fell amid their thick array. Perceiving that his principal loss was occasioned by the cannon, Lautaro gave orders to one of his bravest officers, named Leucoton, to sally from the camp with a select detachment of troops, and to gain possession of the cannon at all events, or never more to appear in his presence. Leucoton executed his orders with the utmost bravery, and after a furious and bloody contest with the guard of the guns, carried them off in triumph; while Lautaro, to prevent the Spaniards from sending succours to their artillery, made a furious general attack on the whole line with all his troops. Astonished by this bold and general attack, and dismayed by the loss of their cannon, the Spanish horse and foot fell into confusion and disorder, and were so furiously pressed upon by the valiant Lautaro and his troops, that they dispersed and fled with the utmost precipitation. Three thousand of the Spaniards and their Promaucian allies were slain in this decisive battle, Villagran himself, having fallen in the retreat, was on the point of being taken prisoner, when he was rescued by the almost incredible efforts of three of his soldiers, and remounted on his horse. The remaining Spaniards urged on their almost exhausted horses to regain the narrow defile where the engagement had commenced, and were closely pursued by the Araucanians; but on arriving at the pass, they found it blocked up with trees, which had been felled across by orders of Lautaro. The engagement was renewed at this place with the utmost fury, and not a man of the broken army would have escaped, had not Villagran opened the pass at the utmost hazard of his life. Though the Araucanians had lost above seven hundred men in the course of this eventful battle, they continued the pursuit a long way; but at length, unable to keep up with the horses, and exhausted with excessive fatigue, they gave up the pursuit, and Lautaro encamped for the night to refresh his men, determined upon passing the Biobio next day to follow up the consequences of his glorious and decisive victory.

On the arrival of the few Spaniards at Conception who had been able to escape from the slaughter at Mariguenu, the city of Conception was filled with indescribable grief and dismay, not a family but had to deplore the loss of some near relation; and the alarm was greatly increased by learning that Lautaro was fast approaching with his victorious army. As Villagran considered it to be impossible to defend the city under the present dismay of his small remaining force, he hastily embarked all the old men, women, and children on board two ships that happened to be then in the harbour, one of which he ordered to proceed to Imperial, and the other to Valparaiso, while he proceeded by land for St Jago with all the rest of the inhabitants who were able to carry arms. Lautaro entered the city next day without opposition, which he found entirely deserted of its inhabitants, but filled with much valuable booty, as by its mines and commerce it had already attained considerable opulence, and the inhabitants were in such haste to escape with their lives, that they only took what provisions they could procure along with them, and abandoned their riches. After removing every thing that was valuable, Lautaro burnt all the houses, and razed the citadel and other fortifications; after which he returned with his army to Arauco, to celebrate his triumph after the manner usual in his country.

While Lautaro thus bravely asserted the independence of his country on the frontiers, Caupolican marched into the south, as has been already mentioned, to invest the cities of Imperial and Valdivia, both of which he held closely blockaded. In this emergency, the governors of these two cities demanded succours from Villagran; who, notwithstanding his late terrible defeat, sent a sufficient number of troops for their defence with all possible speed; and both places being accessible by sea, these succours were able to arrive in time to prevent Caupolican from gaining possession of either.

"When the army of Caupolican drew near to the city of Imperial, the air was suddenly enveloped in black clouds, whence arose a mighty storm of hail and rain. In the midst of the tempest the epumanon or war god of the Araucanians, made his appearance in form of a terrible dragon, casting out fire at his mouth and nostrils, and desired them to hasten their march as he would deliver the city into their hands, on which occasion he enjoined them to put all the Christians to the sword. The epumanon then disappeared, and they pursued their way joyfully, being animated by this oracle. On a sudden the heavens cleared up, and a most beautiful woman was seen, seated on a bright cloud, and having a charming yet severe and majestic countenance, which much abated the pride and haughtiness inspired by the former vision. This was the queen of heaven, who commanded them to return to their own homes, for God was resolved to favour the Christians; and they immediately obeyed70."