Carlisle, owing to its position in the British kingdom of Strathclyde, has preserved a purely Celtic name.  It is the Luguvallum or Luguvallium of the Antonine Itinerary, the Lugubalum and the Luguvalio ad Vallum of the Ravenna geographer, and Bæda's Lugubalia, which was corrupted into Lluel, Simeon of Durham speaking of "Lugubalia, which is called Luel."  With the British prefix caer, a "city," this became Caer-luel.  In the ninth century we find the Anglo-Saxon equivalent Lul-chester, but in the tenth we again find the British form Caer-luel, which degenerated into Carliol, and finally became CARLISLE.  Carlisle was at one extremity of the vallum of Hadrian, which extended from Wallsend to Carlisle.  Lugu-vallum signifies the "wall-tower," that is the tower or fort at the end of the vallum.  The Celtic lugus of Mela, and the Cornish lug, meaning a tower, is seen in the name Lugdunum, "tower-hill," now Lyons. (Names and Their Histories, Taylor, 1898)