up to and during the roman occupation of britain, the native inhabitants of iron age britain spoke "brythonic" languages (a sub-family of the celtic languages) and were regarded as britons (or brythons). the area of modern wales was divided among a number of tribes, of which the silures in modern south-east wales and the ordovices in central and northwest wales were the largest and most powerful. these two tribes were the ones who put up the strongest force to the roman invasion: mona (the island of anglesey) was only conquered by gnaeus julius agricola in 78 ad.