An Ancient Chinese Capital. Earthworks at Old Ch'ang-an
Not least in interest among subjects of archaeological study is that which has to do with the types of fortification constructed by organized communities in the past. These, once the habit of town-dwelling had become fixed, seem to have tended to fall into two major classes : the arx, acropolis, or citadel, one of whose functions it was to provide a temporary refuge in emergency; and the enceinte or city-wall proper, designed to afford permanent protection to the group living within it. Sometimes the two forms occur in combination; more often, singly.The first type we frequently, though by no means always, find situated on a height ; the acropolis of Athens and the Capitoline Hill at Rome are familiar examples. The second class, on the other hand, seems to have developed more especially in those alluvial plains on which sprang up the great river-valley civilizations of the Ancient World. To it belong the tremendous earthworks constructed slightly over two thousand years ago about the city of Ch‘ang-an (meaning ‘Long Peace’ ; possibly Ptolemy’s ‘Sera Metropolis’), the capital of the then recently established Chinese empire.