Mesopotamia.— The configuration of the land exposed the cities of Chaldwa, Assyria and Babylonia to easy attack, for the flat character of the territory made siege from four sides possible. Hence it is that military architecture, forced to meet the added hazards of the locus, received a mature study and development that had not occurred elsewhere in the pre-classic world. It was in Asia that the early develop ments of the art of war construction, which subsequently formed the basis of the Roman, Visigothic and Medieval science, was through necessity established, Numerous ruins serve to show us the character of the Chaldwo-Assyrian protective scheme. Typical of every phase of this art was the city of Dur-Sharrukin, the modern Khorsabad and site of the palace Sar gon. The ancient city was surrounded by a wall 150 feet wide and 60 feet high, furnished with battlements, towers and outworks, and entered by means of arched gateways flanked by pro tecting towers. The palace of the ruler stood upon a stupendous platform constructed strad dling the northwest wall. The position of the palace gave to it the maximum amount of pro tection from within and from without the city.
Greece.— Early Greece was settled by wandering tribes. Tribal equality ceased when unusual strength established local domination on the part of a family or a tribe that had waxed powerful. This condition forced, for protection, a union of local interests—through the establishment of these confederations the Greek city came into existence. Religion and daily life were indissolubly connected in Greece, and the acropolis or upper city of the Hellenes was graced with the monuments erected in honor of the beneficent gods who were every where the guardians of the city and society. In the Orient the protected heights that the Greeks reserved for their shrines were pre empted by the luxury-loving despots as the safest place for their court buildings and pal aces. Athens, with its Acropolis crowned by the noble Parthenon, was the sacred centre of the Attic life, and upon its safety was lavished the thought and ingenuity of the military ex perts of the time. Its capture and sack by the Persians forced a reconstruction of all of its defenses. Under Themistocles, the Athenian leader, the entire city was surrounded by a strong wall and the Pirirus, the port of Athens, was fortified and its harbors protected by moles. Subsequently the city and port were joined by long walls; thus making it possible to control the Attic lands as well as her mari time interests. These extensive military con structions embody everything that the Greeks thought would be of value to them, with which they had come in contact through the wide spread medium of the Delian League. The knowledge thus gained was later absorbed by Magna Grmcia and Sicily.
Rome.— The Romans exhibited an extraor dinary genius for organization and adaptation.
The site of a Roman city was usually selected on territory sloping toward a river. If the area chosen were terminated by another embank ment sloping in the opposite direction, a perfect site, from the Roman point of view, was avail able. The city with its walls flanked on one side by the river was approached by a bridge, the end of which on the bank opposite the city was defended by a tete-de-pont. Within the walled area or enceinte a castle was constructed which commanded the whole system of defense and provided a final refuge for the garrison. If the walls failed, the side of the town opposite the river, on account of the escarpment, was difficult of access and the protecting wall on this side was comparatively easy to defend. The walls connecting the river walls and the escarpment walls presented the weakest parts of the fortifications. It was therefore neces sary additionally to protect the towers and walls in this position with ditches. In order that the defenders might harass the flank of besiegers, the gates were flanked with towers that pro jected well out from the walls. The Romans took care not to surround a hill with a wall. Their principle was to carry a defense wall across the summit of the elevations of any city site. The typical example of the Roman sys tem, as carried out on a great scale, is the city of Rome herself. The Romans, according to Vezetius, found that the enclosure of a for tified place ought not to be in one continuous line, for the reason that battering rams would thus be able too easily to effect a breeching; whereas, by the use of towers placed sufficiently close to one another in the rampart, greater safety would be provided. In erecting the walls for their fortifications of cities, the Romans built two strong walls of masonry separated by an interval of 20 feet, which in terval was filled with the spoil from the extra mural trenches. This fill formed the base for a parapet walk. The Roman military camp, curiously enough, has exerted a tremendous influence upon civil architecture. This is be cause the Emperor Diocletian, upon his abdi cation, laid out at Spalato, in Dalmatia, a great palace based upon the plan of the military camp. The carefully cut masonry walls en closed a rectangular space. Four gates gave access to the palace city, one in the centre of each of the walls. Two intersecting avenues connected these entrances. In the usual camp, the quarters for officers and soldiers were built of brick or wood. The general-in-chief was provided with elaborately protected quarters adjacent the Praetorian or principal gate. In the Castra, palace of Diocletian, quarters for servants and for the guards were constructed. At Mousmieh, the ruins of the Prwtorium or Guard-house, with its curious handling of con structive detail, established an architectural type which exerted notable influence on later work.