Agreda is the typical case of a Castilian town by the border. The kingdoms of Castile, Navarre and Aragon wished it. Very frequently, the peace from the Iberian Peninsula was at stake within its limits. It was the meeting point of three cultures: Arabic, Jewish and Christian. Reconquered by Alphonse I The Battler in 1118. It was repopulated by people from the northeast of Soria: Yanguas, San Pedro Manrique and Magaņa, during Alphonse VII. All the Castilian monarchs, during the Middle Ages, gave this town a large quantity of privileges, so that it remained loyal to them to the detriment of the other bordering kingdoms. This period gave rise to royal weddings (in 1221 James I The Conqueror married Lady Eleanor from Castile), pacts, meetings and quartering.

From this glorious past it still remains a vast and very important cultural legacy. The three cultures immortalized its presence in Agreda. The Arabs built fortresses, from which some wall ruins remain, and two doors from the Caliphal period. The streets that shaped the Jewish quarter have their original plan. The Christians occupied the rest of the town that had a characteristic aspect that still persists today, with abundant religious and civil buildings. The Venerable Sister Mary of Agreda deserves a special mention. This nun that belonged to the discalced Franciscan order led all her vital activity within this extremely narrow-minded atmosphere, Agreda that saw her birth and, since she was 17, the walls of an enclosed convent. Voluntary confinement that would not prevent her from becoming one of the most influential and relevant women from XVII century, as the epistolary relation kept with Philip IV reveals. Her literary personality was materialized in a vast production of works, among them "The Mystic City of God " stands out.