 The latter conquistador ousted the indigenous population and founded the city of Santiago.Valdivia also arrested and took hostage the Cacique (tribal leaders and chiefs) to weaken the society of the local Mapuche people.Blumenthal took part in the defence of the Spanish settlement of Santiago when the Mapuche launched a counter-offensive on 11 September 1541 in attempt to free their caciques held hostage by the conquistadores.