Towns, large or small, rapidly increased in size and number, this followed the stability of the Flavian dynasty in Rome and Agricola implemented the policy of urbanization in Britain itself, it received a further impetus from the need to provide more tribal centers after the death of Cogidubnus. While the campaigns in Wales and Scotland drew troops and garrisons away from the south-east where civilian administrations and urbanization could begin to expand. Still further growth resulted from Emperor Hadrian's visit in 121AD. His new policy of creating a permanent frontier in the north involved removing military units from the forts of Wales, construction of Hadrian's Wall was no new idea, even the Celts had built defensive walls as the name Carlisle suggest, the name Carlisle derives from, 'the wall of the god Lugus'.