During the sixteenth and seventeenth centuries, El Real Monasterio de El Escorial and La Granjilla de La Fresneda were places in which the temporal power of the Spanish monarchy and the ecclesiastical predominance of the Roman Catholic religion in Spain found a common architectural manifestation. El Escorial was a monastery and a Spanish royal palace. Philip engaged the Spanish architect, Juan Bautista de Toledo, to be his collaborator in the design of El Escorial. Juan Bautista had spent the greater part of his career in Rome, where he had worked on the basilica of St. Peter's, and in Naples, where he had served the king's viceroy, whose recommendation brought him to the king's attention. Philip appointed him architect-royal in 1559, and together they designed El Escorial as a “perpetual home for the Catholic Crown of Spain”. It has also been called “an expression in stone of Catholicism in Spain”.
On November 2, 1984, UNESCO declared The Royal Site of San Lorenzo of El Escorial a World Heritage Site as it was so interesting . Now it is an extremely popular tourist attraction, often visited by day-trippers from Madrid.
El Escorial is situated at the foot of Mt. Abantos in the Sierra de Guadarrama. It is a bleak, semi-forested, wind-swept place that owes its name to nearby piles of slag or tailings, called scoria, the detritus of long-played-out iron mines in the Guadarrama.
This austere location, hardly an obvious choice for the site of a royal palace, was chosen by King Philip II of Spain, and it was he who ordained the building of a grand edifice here to commemorate the 1557 Spanish victory at the Battle of St. Quentin in Picardy against Henry II, king of France. He also intended the complex to serve as a necropolis for the interment of the remains of his parents, Charles I and Isabella of Portugal, himself, and his descendants. In addition, Philip envisioned El Escorial as a center for studies in aid of the Counter-Reformation cause.