Satisfied with the extent of the conquests he had made, or rather with the incursions he had been able to make in the Araucanian territory, Valdivia now retraced his steps towards the north; and in his progress during the year 1553, he built fortresses in each of the three Araucanian provinces of Paren Tucapel and Arauco. From the warlike inhabitants of these provinces especially, he apprehended any attempt that might prove fatal to his more southerly settlements of Imperial Villarica and Valdivia, and he left garrisons in these more northern fortresses to preserve the communication, and to be in readiness to afford succours to the others in the south. According to the poet Breilla, the Spaniards had to sustain many battles and encounters with the natives in the course of this expedition in Araucania, but the particulars of none of these are recorded. This is however very probable; as it is not easy to account for the continuance of Lincoyan in the command on any other principles. It may be concluded, however, that, owing to the caution, or cowardice rather of the Araucanian toqui, these actions were so ill conducted and so inconclusive, as to give very little interruption to Valdivia in his triumphant progress through these provinces, between the Biobio and Callacalla, or from Conception to Valdivia.
On his return to St Jago, the seat of government, Valdivia received a considerable body of recruits to his army from Peru, together with 350 horses; on which he dispatched Francisco de Aguirre with two hundred men, to reduce the provinces of Tucuman and Cajo on the eastern side of the Andes; not considering how inadequate was even his whole undiminished military force to retain so large an extent of country as that he had now occupied, and a so numerous and warlike people under subjection. Indefatigable in the execution of his extensive plans of conquest, Valdivia returned into Araucania, where he founded in the province of Encol, a city to which he gave the name of La Frontera, being the seventh and last of his foundation. This name, from events which could not then have been in the consideration of Valdivia, has become strictly applicable to its present situation, as its ruins are actually situated on the southern confines of the Spanish settlements in Chili. Though long ago destroyed, it is still mentioned by geographers as an existing city under the name of Angol, by which native denomination it was long known to the Spaniards. It was situated in a fertile district, excellently adapted for the cultivation of vines, and for some time was in a rich and flourishing condition, principally owing to its wines, which were in great repute at Buenos Ayres, to which place they were transported by a road across the Andes and through the plains of La Plata.
After making suitable regulations for the security of this new colony, Valdivia returned to his favourite city of Conception, where he instituted three principal military officers for commanding the royal army of Chili, consisting of a quartermaster-general, a serjeant-major, and a commissary. In the present times only two of these subsist, the quarter-master-general and the serjeant-major; which latter office is now divided into two, one for the cavalry, and the other for the infantry; while the office of commissary is only now known in the militia. At this time he sent Alderte into Spain, with a large sum of money, and a particular relation of his transactions and conquests; and commissioned him to employ his utmost exertions to obtain for him the perpetual government of the country which he had conquered, together with the title of Marquis of Aranco. He dispatched likewise Francisco de Ulloa by sea, with directions to explore the Straits of Magellan, by means of which he hoped to open a direct communication with Spain, without being obliged to depend upon Peru for supplies.
While occupied in the contemplation of these extensive plans for the amelioration of the extensive kingdom which he had subdued, and the advancement of his own rank and fortune, Valdivia had no suspicion of an extensive and determined system of warfare which was planning among the Araucanians, and which soon burst forth with irresistible violence, to the ultimate destruction of all the Spanish conquests beyond the Biobio, and to which Valdivia himself fell an early victim. Colocolo, an aged Ulmen of the province of Arauco, animated by love for his country, quitted the retirement in which he had long indulged, and traversed the provinces of the Araucanian confederacy, exciting with indefatigable zeal the dormant spirit of his countrymen, which had sunk after their late disasters, and eagerly solicited them to make choice of a new supreme toqui capable of directing their arms for the recovery of those parts of their country which had been subjugated by the Spaniards, through the timid conduct of Lincoyan. Colocolo was well versed in the principles of government which subsisted among the Araucanians, and had long enjoyed the reputation of wisdom throughout the whole country, in which he was so universally esteemed and respected, that his councils and opinion were always solicited and listened to on every subject of importance. Roused from their torpidity by his animating exhortations, the whole body of Araucanian ulmens assembled according to their custom in a Butacayog, or national council, in an open plain; and, after the usual feast, they proceeded to consult upon the situation of their national affairs, and the election of a new toqui to wipe off the disgraces which they had suffered under the direction of Lincoyan.
Many chiefs aspired to the glorious situation of avenger of their oppressed country, the most distinguished among whom were Andalican, Elicura, Ongolmo, Renco, and Tucapel. The last of these was so highly celebrated by his martial prowess that the province of which he was Apo-ulmen has ever since retained his name. He was besides supported in his pretensions by a powerful party; but his elevation to the supreme command was opposed by the more prudent members of the assembly, who dreaded lest the impetuosity of his character might hasten the entire ruin of the nation, instead of retrieving their honour and independence. Dissensions arose so high that the opposite parties were on the point of turning their arms against each other, when the venerable Colocolo rose to speak, and obtained a patient and attentive hearing. By a judicious and energetic address, he pacified their factious irritation so completely, that the assembly unanimously submitted the nomination of a supreme toqui to his choice. The wise old man, on whom every eye was now fixed in anxious expectation, immediately named Caupolican, the ulmen of Pilmaquen a subordinate district of the province of Tucapel, and the whole assembly applauded and confirmed the choice. Caupolican was of a lofty stature and uncommon bodily strength; and though he had lost an eye, the majesty of his countenance evinced great endowments of mind. He was of a serious, patient, and sagacious disposition; and besides great personal bravery, had every requisite to constitute him an able general of the peculiar troops over whom he was now appointed to command. On being invested with the battle-axe, as the badge of his supreme authority, he immediately selected the officers who were to bear command under him in the army of the state, among whom were all the late competitors, and even Lincoyan the former toqui. The office of vice-toqui, or lieutenant-general, he conferred on Marientu, a person in whom he reposed entire confidence. Even the violent Tucapel, who had nearly involved his country in civil war for the attainment of the supreme command, did not disdain to serve under the orders of his own vassal, manifesting by this submission his eager wish to sacrifice his personal ambition to the service of his country.