It is part of the Alarcos-Calatrava Archaeological Park.
The castle is at the top, built on an artificial platform. Its plan is rectangular and it has nine towers, seven square and two pentagonal in the bow. It was occupied by Iberians, Romans and Arabs.
In 1195 a great battle took place here, the Battle of Alarcos against the Almohads, in which Alfonso VIII had to flee wounded in the leg. After the war, Alarcos and its surroundings remained in Almohad power, which delayed the Reconquest for several decades.
This Battle took place in the plain that today extends between Alarcos and Poblete.