Isca, variously specified as Isca Augusta or Isca Silurum, was the site of a Roman legionary fortress and settlement or vicus , the remains of which lie beneath parts of the present-day suburban village of Caerleon to the north of the city of Newport in South Wales.Headquarters of the Legion "II Augusta", which took part in the invasion under Emperor Claudius in AD 43, Isca is uniquely important for the study of the conquest, pacification and colonisation of Britannia by the Roman army.