Built in the late 12th or early 13th century on a sandstone outcrop in the Sierra de Caldereros, it stands on the site of a former Visigothic and Moorish fortification that fell into Christian hands in 1129.

In Spanish speaking countries the word zafra refers to the late summer or early autumn harvest of crops such as sugarcane, a staple brought from Arab lands.

[4] Traces of buildings – possibly part of an outer enclosure that might have incorporated structures such as stables or supply stores – can be seen in the meadow surrounding the castle.

Its exterior is freely visible, but visits to its interior require the permission of the owners, the family of Antonio Sanz Polo of Molina de Aragón.

[3] According to Antonio Herrera Casado, visitors can expect to be "surprised at the beauty of the scene, the ferocity of the rocks and walls, the battlements, and especially the valiant towers visible to the astonished audience.

The Kingdom of Aragon took it over to serve as a key defensive position in the south of its territory, to guard the newly created community of town and land (comunidad de villa y tierra) of Daroca.

Its defences were put to the test in 1222 when Don Gonzalo Perez de Lara, the third ruler of Molina, aroused the hostility of King Fernando III of Castile.

Don Gonzalo had committed a series of excesses in territories adjoining his fief, including attacks on villages held by neighbouring lords.

Under the Agreement of Zafra, the Señorío de Molina would be inherited on Don Gonzalo's death by his daughter Doña Mafalda, who would marry Fernando's son Prince Alfonso, thus bringing the territory under the Crown's control.

Its castellan, the famous Don Juan de Hombrados Malo, managed to see off all opponents and maintained the crown's control of the castle until it finally passed into the hands of the Catholic Monarchs of the unified kingdoms of Castile and Aragon in 1479.

The reconquest of the Iberian peninsula and the merger of the two kingdoms deprived the castle of its former strategic importance, and from the 16th century onwards it began to fall into ruin.