interior of tombs,[285] and an early example of the same motive can be seen in the gateway at Perge, a city which lay under the direct influence of Antioch.[286] The lightening of the massive wall by means of niches and blind openings can be traced through pre-Greek architecture in Mesopotamia (Assyrian palaces and temples) and in Egypt (from the Eighteenth Dynasty and even earlier) down to the Achaemenid period. The systematic application of this principle to the wall-face, and its union with imitative architecture in relief as a decorative scheme took place, as far as can be determined at present, in the Hellenistic age. In the third and in the second century B.C. the division of the wall into two zones by means of a moulding appears at Delos, Priene, Magnesia, and other parts of western Asia,[287] and a little later it is found in what is known as the incrusted style at Oscan Pompeii. The lower zone consists of unpainted stucco decoration representing a stone wall, composed of one or of two rows of orthostatae, and above them several courses of dressed stones. The upper zone, which was at first undecorated (it represented space, the upper air), takes on later the semblance of a colonnaded gallery[288] in imitation of the open galleries characteristic of Eastern Hellenistic architecture.[289] The podium façade carrying an open arcade is, as Professor Delbrück is careful to point out, in origin different from the galleried wall, but in façade schemes the two run together so as to be almost indistinguishable. The theme is represented in relief upon the façade of the Bouleuterion at Miletus[290] and frequently in Pompeii, where, however, the engaged columns do not stand upon a podium.[291] Behind the columns, both at Delos and in the Pompeiian examples, the wall is still divided into two zones by a moulding. In all cases it is a theme which stands as a representation in relief of plastic architecture, of deep colonnades such as those which were to be seen on the Mausoleum at Halicarnassus.[292] The blind order of the Ephebeum at Priene may be cited as another striking example of imitative architecture.[293] Similarly the superimposition of one blind order upon another, a decorative motive so familiar in Roman theatres and amphitheatres, finds its prototype in the colonnades of Hellenistic stoae, such as those erected by Attalus in Athens and in Pergamon.[294]