Archivo General de Simancas

Archivo General de Simancas is a state archive in the town of Simancas in Valladolid province, housed inside a stone fortress from the 15th century. The building stands on high ground above the Pisuerga River and holds millions of written records from the Spanish Crown's administration between the 16th and 19th centuries.

Charles V founded the archive in 1540 as a central storage site for government documents of the Castilian Crown, after records had previously been scattered in different palaces and monasteries. In the 18th century the collection was reorganized under Philip V, with many papers moved to Cádiz and Seville.

The collection includes handwritten letters and seals from rulers who governed across several continents, as well as treaties with Ottoman sultans and North African kingdoms. Visitors today can follow how administration and diplomacy worked in the early modern period by observing the different writing systems and languages used.

Researchers must register in advance and can request up to ten document bundles daily through an electronic system. The rooms are climate controlled to protect the old papers, so warm clothing is recommended.

The fortress itself originally served as a prison for nobles and was only later converted into a document storage facility. Some of the oldest papers still bear water stains and traces of insect damage from past centuries, before modern conservation was introduced.