According to the poetic work La Araucana the primary known wife of Caupolican was Fresia, although she is also named Gueden or Paca by other authors. His only known child was named Lemucaguin, or Caupolican the younger. According to tradition and the writings of Fernando Alegria, Caupolican was of a grave countenance and was blind in one eye from childhood.
Caupolican fought from his youth on against the Spanish Conquistadors helping to achieve the freedom of his people. He was elected Toqui of the Mapuche people, as Lautaro’s successor (although Alonso de Ercilla states he was elected previously and that he was a secret candidate for this office chosen by Colo Colo to conduct the War of Aurauco). It appears that Caupolican was a member of a very respected family in Mapuche society, seeing as he and his brothers were always in the group of military leaders who planned battle strategies for the tribe.
The Mapuches are a people who resisted the Spanish conquista of southern Chile. Together with Lautaro, Caupolican was one of the leaders of the Mapuche people in the wars of the sixteenth century. Caupolican cooperated with Lautaro in the Battle of Tucapel and the subsequent hostile takeover of the Tucapel fort, in which the Spanish army was defeated and their commanding officer Pedro de Valdivia was killed. The execution of Pedro de Valdivia is attributed to Caupolican by the historian Jeronimo de Vivar. The name Caupolican became a symbol of Native American resistance, and his life and acts were collected by Alonso de Ercilla - one of the military captains in the army of Garcia Hurtado de Mendoza y Manrique - in his epic poem La Araucana and by Ruben Dario in his poem Caupolican. The primary conflicts of the Arauco War in which Caupolican participated were: The Battle at Lagunillas as a soldier, and the Battles of Millarapue and Cañete as Toqui.
After the death of Lautaro, the Mapuche people were left without an effective leader to guide them into battle; evidence is shown of this perilous situation in the combat of the Fort of San Luis, which they failed to take, and in the battle of Lagunillas on 5 September 1557. In this battle an army of 12,000 Mapuche warriors at the command of several Toquis - among them Lincoyan and Galvarino- attacked a large Spanish army lead by Garcia Hurtado de Mendoza. As he passed the Biobio river, coming from Concepcion, Garcia lead a force of 600 well armed soldiers and 1500 yanakunas, who were attacked by the Mapuche forces in a marsh named "lagunillas".
The attack was highly disorganized, and despite the great numeric difference, the Mapuche were defeated in brutal hand-to-hand combat; leaving hundreds of dead and injured and 150 prisoners of war. Among these prisoners was one of the Toquis: Galvarino. Garcia Hurtado de Mendoza, ordered his soldiers to mutilate the right hand and nose of the prisoners to teach them a lesson. Galvarino not only extended his right hand to be amputated, but also extended his other hand before the soldier ordered to cut his hand off and both were amputated before he was freed. This type of lesson infuriated and hardened the Mapuches even more towards the usurpers of their territory.