In this paper, we will study the fortress of Taibilla, a defensive complex built by the Order of Santiago in the middle of the thirteenth century in a strategic point of the Sierra de Segura, currently belonging to the municipality of Nerpio (Albacete). Although the complex was built at the top of the hill on whose hillside a relatively important town existed in Andalusian times, the archaeological excavations proved that most of the remains of the fortification currently visible were built after the Christian conquest. It is a stately castle and the outer enclosure that protected the Christian town, both of notable importance since they were destined to accommodate a comendador and a council respectively. The Encomienda de Taibilla, however, disappeared within a few years due to the avatars of the border, leaving its territory incorporated to that of Yeste. For this reason, the fortress of Taibilla hardly underwent modifications in the medieval period, so that it has been fossilized as an excellent example of the santiaguista stately architecture of the middle of the thirteenth century.