At Narbonne one is at the very heart of the Midi. It is an ancient mother city of Europe, a capital of Celtic Gaul. Surpassed by nothing in the Roman world, Narbonne kept its pre-eminence under both pagan and Christian Rome. It became the seat of the Visigothic royal line, and of their Moorish conquerors. Charlemagne made it a fortified outpost, and during the Middle Ages it was the richest of trading centers, a third of whose population was Jewish. In 1311, the same covetous king who abolished the Templars banished the Jews, to whom Charlemagne had given the freedom of this town for their support of his cause against Islam. To-day one walks its dust-white streets with a strange sensation of loneliness. Narbonne is a dead city. When in the latter part of the XIII century the great Gothic cathedral of St. Just was begun, there seemed no reason why so flourishing a trading center could not succeed in the enterprise. Unlike Beauvais, where the chief church was from its inception out of all proportion to the population, Narbonne could easily have erected a nave to complete its mighty choir. In 1272 was laid the first stone of St. Just Cathedral.[239] Then there occurred here what happens to all rivers that communicate with the sea by means of lagoons: gradually the salt lakes silt up till they become marshes through which the river winds tortuously till suddenly it breaks a new path to the sea. In 1320 occurred this catastrophe for Narbonne. The Roman dike gave way and the river Aude left its ancient bed, quitting Narbonne to flow toward Courson, where it still is. The stagnant waters bred disease, and the metropolis, greeted by Sidonius Apollinaris for its salubrity, _Salve Narbo, potens salubritate_, became a pestilential site. Narbonne sank into silent decay. Over the shrunken city stands the ghostly fragment of the great cathedral, surpassed in height only by Beauvais and Amiens. St. Just was begun in 1272, and three years later the cathedral of Toulouse was started on a plan and with profiles so closely resembling Narbonne's chief church that one master may have designed both. Both derive immediately from those northern Gothic churches translated with a meridional accent, the cathedrals of Clermont, whose choir was finished in 1265, and of Limoges, begun in 1273.