Alcazar castle in Segovia, Spain, was first mentioned in records dating back to 1122 as a hill-fort set atop a rocky outcrop between the rivers Bergsma and Clamores. By 1155 this hill-fort became known as “Alcazar”, which in Arabic meant royal residence. Alfonso VI was the first of the Spanish kings to modernise the castle. Alfonso X "The Wise" made Alcazar castle into one of his favourite residences.
In the 14th century the castle was the centre of a fight between factions of the nobility. The use of cannons caused Alcazar to strengthen her walls and extend its defences as the nobility fought for control. The fortress played an integral part in Isabella being crowned Queen of Castile.
Around the start of the 13th century, Alcazar castle was again altered and enlarged. King John II during the period 1405 and 1454 extended the moat that surrounded the castle. He also extended the east tower which bears his name.
King Phillip II married his fourth wife, Anne of Austria at Alcazar. He also covered the roofs with conical slate spires which were popular in Central Europe at the time.
Alcazar castle played an important role during the civil wars in the 19th century and was used as a prison until 1764, when it became the Royal School of Artillery. The school was moved to the Convent of Saint Francis after a fire in 1862 destroyed many of the castles roofs. It was restore some twenty years later in a romantic style grander than the original building.
In 1898, the General Military Archives were moved to the castles upper floors and in 1953; the "Patronato del Alcazar" (Alcazar Trust) of Segovia was created.