The process of incorporation did not stop at the Maule, but included the Promaucians and most of the other tribes between that river and the Biobio. Beyond the latter stretched the Araucanian territory for two hundred miles, and Valdivia now undertook the conquest of the southern forests where the Inca arms had never been able to penetrate. His first step was to found Concepcion near the mouth of the Biobio. The neighbouring territory belonged to allies of the confederacy, and the Araucanians felt great alarm at such an aggression. The grand council was summoned, composed of the head-chiefs of the four nations, and the chiefs--called ulmens--of the provinces and tribes into which these nations were divided and subdivided. In accordance with immemorial custom, the deliberations lasted three days, and the humblest warrior was permitted to give his opinion before war was voted. Once the determination reached and a general, or "toqui," elected, each soldier put on his leather cuirass, picked up his heavy war club, and, four thousand strong, the tribesmen sallied forth to attack the Spaniards. Musketry volley and cavalry charge compelled the Araucanians to retreat, after a hotly contested combat which lasted several hours. These Indians, strong and sturdy dwellers in an invigorating climate, were more formidable foes than the Spaniards had yet encountered in South America. Though amazed at the deadly effect of the strange weapons which the invaders used, they were not demoralised. Like the Saracens they believed that death in battle was a passport to paradise, war was their principal business, and the youth were trained up to the trade of arms. At close quarters they were almost irresistible; their clubs and spears, wielded with reckless bravery, matched the swords of the Spaniards, and as soon as they learned how to take advantage of cover in approaching an enemy provided with firearms, the result of a battle between them and the Castilians became doubtful.