The Romans, ‘the most city-proud people known’, founded their city-policy and urban ideology principally on their own city. The Romans saw the city as an instrument of civilization, as a means of taming the barbarians whom they had incorporated into their empire. The city replaced the hillfort. It was, as a general rule, carefully planned with straight streets intersecting at right-angles. Generous space was allowed for temples and basilicas or large halls, which served as public meeting places, for the forum, or central square, around which these buildings were grouped, and for the theater, where dramatic shows were performed, and the amphitheater or arena, where more brutal games were staged. The underlying street pattern and urban morphology of many European and Mediterranean towns and cities can be traced back to a Roman grid plan. The military expansion of this period facilitated the adoption of the grid form as standard: the Romans established castra (forts or camps) first as military centres; some of them developed into administrative hubs.Roman castra were often sited on flat land, especially close to or on important nodes like river crossings or intersections of trade routes. The dimensions of the castra were often standard, with each of its four walls generally having a length of 660 metres (2,150 ft). Familiarity was the aim of such standardisation: soldiers could be stationed anywhere around the Empire, and orientation would be easy within established towns if they had a standard layout. Each would have the aforementioned decumanus maximus and cardo maximus at its heart, and their intersection would form the forum, around which would be sited important public buildings. Outside of the castra, large tracts of land were also divided in accordance with the grid within the walls.