Under the bronze-weaponed Celts, a very different type of civilisation became possible. In the first place a more extended chieftainship resulted from the improved weapons and consequent military power; and all Britain (at least, towards the close of the Celtic domination) became amalgamated into considerable kingdoms, some of which seem to have spread over several modern shires. Sussex, however, enclosed by its barrier of forest, would naturally remain a single little principality of itself, held, at least in later times, by a tribe known to the Romans as Regni. Traces of Celtic occupation are mainly confined to the Downs and the seaward slope of Sussex Proper; in the broad expanse of the Weald, they are few and far between. The Celts occupied the fertile valleys and alluvial slopes, cut down the woods by the river sides and on the plains, and built their larger and more regular camps of refuge upon the Downs, for protection against the kindred Cantii beyond the Weald, or the more distantly-related Belgae across the Hayling tidal flats. Of these hill-forts, Hollingbury Castle, near Brighton, may be taken as a typical example. Bronze weapons and other implements of the bronze age are found in great numbers about Lewes in particular (where the isolated height, now crowned by the Norman Castle, must always have commanded the fertile river vale of the Ouse), as well as at Chichester, Bognor, and elsewhere. But the great forest, inhabited by savage beasts and still more terrible fiends, proved a barrier to their northward extension. Even if they had cleared the land, they could not have cultivated it with their existing methods; and so it is only in a few spots near the upper river valleys that we find any traces of outlying Celtic hamlets in the wilderness of the Weald. Some kind of trade, however, must have existed between the Regni and the other tribes of Britain, in order to supply them with the bronze, whose component elements Sussex does not possess. Woolsonbury, Westburton Hill, Clayton Hill, Wilmington, Hangleton Down, Plumpton Plain, and many other places along the coast have yielded large numbers of bronze implements; while the occurrence of the raw metal in lumps, together with the finished weapons, at Worthing and Beachy Head, as well the discovery of a mould for a socketed celt at Wilmington, shows that the actual foundry work was performed in Sussex itself. A beautiful torque from Hollingbury Castle attests the workmanship of the Sussex founders. No doubt the tin was imported from Cornwall, while the copper was probably brought over from the continent. Glass beads, doubtless of Southern (perhaps Egyptian) manufacture, have also been found in Sussex, with implements of the bronze age.