Catacombs of Commodilla, on the Via Ostiensis, contain one of the earliest images of a bearded Christ. They originally held the relics of Saints Felix and Adauctus. The hypogeum leading to the catacombs was built in the fourth century. The catacombs were used for burials until the sixth century. Later, as happened to other Christian underground cemeteries, it was transformed into a place of worship of martyrdom: restoration of the basilica underground were made by several popes until the ninth century, a sign that the catacombs were still at that time a place of pilgrimage of devout Christians.
There were also found coins bearing the effigy of Pope Gregory IV (827-844) Pope Leo IV (847-855) finally gave the relics of the martyrs Felix and Adautto the wife of Emperor Lothair. Following the catacombs were abandoned and fell into oblivion. It was discovered in 1595 by archaeologist Antonio Bosio, but the first to identify it as that of Commodilla was in the nineteenth century, Giovanni Battista de Rossi. Restoration campaigns were performed at the beginning of the twentieth century and led to the complete excavation of the second level cemetery.
The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.