According to the old chronicles, the foundation of a monastery in Lorvão dates back to the 6th century. However, the earliest written documents date back to the 9th century and are later than the Christian Reconquest. At that time, the locale was entrusted to the monks of Cluny, responsible for the agrarian development of the surrounding region and the monastery was dedicated to the martyrs of Saint Mamede and Saint Pelágio.