The Indies Archive which used to be the Mercaderes Market, was built in 1572. Designed by Juan de Herrera and built by Alonso de Vandelviva and Juan de Minjares. During the 17th century the second floor and the cross of the Oath were constructed. A century later Carlos (Charles) III chose the building as the site for the Indies Archive. There were consequent modifications made to the building including the rebuilding of the main staircase. A building with a square floor plan with a large central patio. Inside valuable documents are kept that recreate history of the relationship of Spain with the overseas American colonies.