In the department of Ariège are a vast number of natural caverns, many of which have served as places of retreat for the Albigenses. Between Tarascon and Cabannes are some that were defended by crenellated walls, and are supposed to date from the Wars of Religion, but probably go back beyond the time of the English occupation. It is also said that the Huguenots met in them for their assemblies. In the country they go by the name of _gleizetos_, or _petites eglises_. They are found on the left bank of the Ariège. In the fourth century the Priscillianist heretics expelled from Spain settled in the mountains on the north slope of the Pyrenees, and propagated their doctrines throughout the country and among the population more than half pagan, and this explains the spread of Albigensian Manichaeism later. In 407 the Vandals, Suevi and Alani, during three years in succession swept the country, committing frightful ravages, as they passed on their way into Spain; and no doubt can be entertained that at this time the numerous grottoes were used by the natives as refuges. In 412 there was another influx of barbarians, this time Visigoths; their king Walla made Toulouse his capital, and gave over two-thirds of the land to his followers. After the battle of Voulon, in 507, Clovis took possession of Toulouse. In 715 the Saracens poured through the gaps in the Pyrenees, occupied the basin of the Ariège, and destroyed the city of Couserans. In 731 more arrived in a veritable invasion of multitudes, and ravaged all the south of France. Again the caves served their end as places of hiding. The south of France, rich and dissolute, was steeped in heresy. This heresy was a compound of Priscillianism, the dualism of Manes, Oriental and Gnostic fancies, Gothic Arianism, and indigenous superstition, all fused together in what was known as Albigensianism, and which was hardly Christian even in name. The terrible and remorseless extermination of these unfortunate people, who knew no better, by order of Innocent III. and John XXIII., presents one of the most horrible passages in history. The country reeked with the smoke of pyres at which the heretics were burnt, and was drenched with their blood. In 1244 their last stronghold, the Montsegur, was taken, when two hundred of them were burnt alive. Only some few who had concealed themselves in the dens and caves of the earth survived this terrible time. The last heard of them is in 1328, when some of the proscribed took refuge in the grottoes of Lombrive, when 500 or 600 were walled in and starved to death, as already related. In Derbyshire are numerous caves--at Castleton, Bradwell Eyam, Matlock, and Buxton--but they are all natural, except such as are old mine- workings.