The site of the arx of the ancient town is probably to be sought on the hill on which lies the Villa Spada, though no traces of early buildings or defences are to be seen: pre-Roman tombs are to be found in the cliffs to the north.
Though the emperor Julian improved its defences, the town was destroyed by the Huns under Attila, in the 5th century, but Justinian did his best to restore it.
Behind all this huge development of fixed defences lie the central fortresses of Paris and Lyons.
The defences, of the Spanish frontier consist of the entrenched camps of Bayonne and Perpignan and the various small forts darrt of the Pyrenees.
Of the coast defences the principal are Toulon, Antibes, Rochefort, Lorient, Brest, Olron, La Rochelle, BelleIsle, Cherbourg,St-Malo, Havre, Calais, Gravelines and Dunkirk A number of the older fortresses, dating for the most part from Louis XIV.s time, are still in existence, but are no longer of military importance.