Originally , Chillán Viejo was the location of a Spanish fort with the name of '' San Ildefonso '' , which was established in 1565 , during the campaign of Pedro de Villagra against Loble and the Mapuche north of the Biobío River . Ordered in 1579 to establish a city at the site by Governor Rodrigo de Quiroga , Martin Ruiz de Gamboa founded the city on June 25 , 1580 after replacing Quiroga as governor following his death . He gave it the name '' San Bartolomé de Chillán y Gamboa '' and populated it with 50 Spaniards and 60 more in the fort . It suffered a number of attacks before it was destroyed by the Mapuche in 1599 after the Disaster of Curalaba . Governor Francisco de Quiñónez immediately repaired it in April 1599 . Later , in 1655 , the same Mapuche and the neighboring Pehuenches forced the citizens to abandon it again . When it was again reoccupied , it was demolished by an earthquake on March 15 , 1657 . It was repopulated again in 1663 , under Ángel de Saldia . The earthquake of May 25 , 1751 , that ruined old Concepcion , also damaged the city , aggravated considerably by a simultaneous extraordinary flooding of the Chillán River . This forced its transfer two years later to the site that it occupies today
earthquake of May 25 , 1751
1751 Concepción earthquake
Chillán Viejo