It is a mammoth building, with intended reminders of the Temple of Solomon, as described in the Bible.
Indeed, the actor Errol Flynn died there while filming the biblical epic, Solomon and Sheba, on location back in the era of black-and-white cinema films.
The construction of the Escorial cost 5.5 million ducats. By way of comparison, the equipping and sending of the Spanish Armada to invade England in the year 1588 cost Phillip II about ten million ducats.
Neither of these ventures would have been financially possible without the stream of silver and goal coming to Spain from the New World (Latin America) as a tribute exacted by the King of Spain.
The Escorial has twice been devastated by fire, and in 1807 it was looted by soldiers from France.
The chapels of the Escorial had been in charge of the Jeronimite Order until the religious suppression of 1835.
As early as 1855 the Escorial had been offered to the Augustinians of the Philippines missionary province for their use as a seminary instead of their college at Valladolid, but they declined the offer at that point in time.
On 3rd August 1885 they accepted a new offer to have Augustinian communities live in the building.
To this day, the Escorial Province of the Augustinian Order has responsibility for the chapels and sacristies, for the official choir and for the schooling of the members of the choir, etc. They also administer a high school within the vast building.
They also use the building as a novitiate for candidates to the Order, and as a residence for Augustinian professors at the adjacent national university.
The Spanish Civil War (1936-1939) was a time of great difficulty for the Church, and for priests and religious orders in particular.
During that war, sixty five members of the Order of Saint Augustine in the El Escorial were executed.
This included the Augustinian Prior Provincial (regional superior) Avelino Rodríguez O.S.A.. The Assistant General (assistant world leader) Mariano Revilla O.S.A. was also executed.
In all, five groups of Spanish Augustinian friars totalling 180 men lost their lives by execution during the Civil War.