During the seventeenth century, the Port of Valdivia was part of the Mapunche country, liberated in 1599 from Spanish rule. However, the greed of the enemy European powers of the Crown for the dominance of trade routes due to the strategic role of the Port, forced the Viceroy Toledo to take action on the matter, financing the largest expedition of his time to repopulate the city and expel the Dutch corsairs who had established forts in 1643. In alliance with the main toqui of the Mariquina, Juan Manqueante, established in 1645 the first five castles to defend themselves from corsairs and pirates, granting him the status of Plaza and Presidio.
Valdivia is annexed to Chile in 1820 and the castle remains in the fog. The Monument was reconstructed and protected by law in 1950, work led by Roberto Montandón, recreating the Spanish constructions of the 18th century. The building of the permanent exhibition of the Castillo de Niebla Site Museum, the Casa del Castellano, was built on the ruins of the troop barracks, completed in December 1991, and officially inaugurated on 1 February 1992, its construction project it was framed within the commemoration activities of the V Centennial.
As stated in the building plans, the plant has a length of 48.50 m x 8.40 m wide, with a height of the walls that varies between 3.50 m and 3.80 m.
In this building there is an exhibition about the history and characteristics of both Castillo de Niebla and the other fortifications of the Corral Bay and its development; It is composed of information panels, historical objects as well as reproductions of maps, plans and documents.
The Site Museum stands out for its moat and battery carved into the rock itself, which makes it unique in the world, as well as its bastions and exceptional view.