Cave altars from the late Neolithic have been discovered in the area, confirming the presence of former settlers. However, the history of Bonilla de la Sierra began in the 13th century, when it became part of the bishopric of Ávila, followed by the reconstruction of its primitive castle in the 14th century, residence of the king of Castile Juan II a century later, and of several prelates until the confiscation of Mendizábal in the 19th century. It came to be known as 'bonna villa,' for being an excellent resting place. At the beginning of the 16th century, the people of Avila had established their own ordinances for the town and the estate, of which Bonilla was to be head.