John Davies, the Brythonic languages spoken throughout Britain resulted from an indigenous "cumulative Celticity", rather than from migration. Roman era The Roman conquest of Wales began in AD 48 and took 30 years to complete; the occupation lasted over 300 years. The most famous of resistance was led by Caradog of the Celtic Catuvellauni tribe (modern day Essex), which were defeated by the Romans. Now leading the Celtic tribes of the Ordovices and Silures (of present day Monmouthshire), Caradog led a successful guerilla war against the Romans. His armies were eventually defeated at the Battle of Caer Caradog on the Anglo-Welsh border in AD 50. Caradog was later taken to Rome and gave a speech, impressing the Roman emperor to the extent that he was pardoned and allowed to live peacefully in Rome. The Roman conquest was completed in 78, with Roman rule lasting until 383. Roman rule in Wales was a military occupation, save for the southern coastal region of South Wales east of the Gower Peninsula, where there is a legacy of Romanisation. The only town in Wales founded by the Romans, Caerwent, is located in South Wales. Both Caerwent and Carmarthen, also in southern Wales, would become Roman civitates. During the occupation, both the region that would become Wales and its people were a mostly autonomous part of Roman Britain. By AD 47, Rome had invaded and conquered all of southernmost and southeastern Britain under the first Roman governor of Britain. As part of the Roman conquest of Britain, a series of campaigns to conquer Wales was launched by his successor in 48 and would continue intermittently under successive governors until the conquest was completed in 78. It is these campaigns of conquest that are the most widely known feature of Wales during the Roman era due to the spirited but unsuccessful defence of their homelands by two native tribes, the Silures and the Ordovices. The Demetae of southwestern Wales seem to have quickly made their peace with the Romans, as there is no indication of war with Rome, and their homeland was not heavily planted with forts nor overlaid with roads. The Demetae would be the only Welsh tribe to emerge from Roman rule with their homeland and tribal name intact. Wales was a rich source of mineral wealth and the Romans used their engineering technology to extract large amounts of gold, copper, and lead, as