This ship replaced the 4 old armoured/protected cruisers that had been the mainstay of the Chilean Navy till the advent of the Royal Navy reparation deal. Because Chile was outside the various Treaties then in force, the Chileans could choose what sort of armament they wanted their new cruiser to carry. The Chileans had had the foresight to buy the twin 10" from the Swiftsure class. Described by Janes Fighting Ships as a light Battlecruiser, the ship was a design by Lillicrap (the cruiser King) while he was chief designer for the Royal Navy.
Being clear of treaties these ships were able to be bigger and were able to have thicker armour for both side and deck armour. Some thought to had been made to dispense with the aircraft handling facilities and use the space to improve the AA armament. However it was felt as no South American country had much of an air force that having scouting facilities, by having their own aircraft aboard, would be an asset.
