The Trastamara kings of Castile already had a hunting lodge in Valsain. But the royal palace itself was built between 1552 and 1556 for King Philip II by the architect Gaspar de Vega after the king returned from a trip to France, England, and the Netherlands. The architecture of the palace was heavily influenced by Netherlandish/ Flemish architecture, such as Binche Palace, features of which were until then unknown in Spain: steeply pitched slate roofs, slated spires, dormer windows.