Several cities are allotted to King Arthur by the romance-writers.  The principal are Caerleon, Camelot, and Carlisle.
    Caerleon derives its name from its having been the station of one of the legions, during the dominion of the Romans.  It is called by Latin writers Urbs Legionum, the City of Legions.  The former word being rendered into Welsh by Caer, meaning city, and the latter contracted into lleon.  The river Usk retains its name in modern geography, and there is a town or city of Caerleon upon it, though the city of Cardiff is thought to be the scene of Arthur's court.  Chester also bears in Welsh the name of Caerleon; for Chester, derived from castra, Latin for camp, is the designation of military headquarters. (Age of Chivalry, Bulfinch, 1901)