In the whole valley, the repopulation allowed by the foundation of several monasteries had great importance. The most important were the San Vicente de Fístoles monastery and the Santa Cruz de Castañeda collegiate church. In addition to the monasteries, several romanesque temples were built during the 11th to 13th centuries, some of which still stand: the aforementioned Santa Cruz de Castañeda church, the Santa María de Cayón church, and the temple of San Miguel de Monte Carceña, among others. These buildings show the peak and the importance that this "comarca" had during those centuries.