Pioz Castle is an old fortification in the Guadalajara province of central Spain. The castle was built in the 15th century by the Don Pedro Gonzalez de Mendoza, the Cardinal of Spain at the time. Located in the southwestern part of the province, the area had lost some of its strategic importance by this time. As the Cardinal focused his attention on other projects, control of Pioz came into the hands of a local noble family, who completed the structure. It subsequently fell into a semi-ruined state.