Hatra, while the inner walls of the town were flanked by rectangular towers, solid or casemated, and casemated bastions, on the outer wall a rounded tower has been recorded, and Dr. Andrae conjectures that it was one of many.[217] In this particular, as in the approximately circular outline assumed by its walls, Hatra may exhibit traits borrowed from the civilization of the southern Hittites. There are rounded and rectangular towers in the larger Parthian palace at Niffer.[218] In Sasanian fortifications the rounded tower seems practically to have displaced the rectangular.[219] [Illustration: FIG. 27. Lagash. (From _L’Acropole de Suse_, by kind permission of M. Dieulafoy.)] Flanking towers strengthened the walls of Hittite cities. At Zindjirli the gradual development of more scientific methods can be traced in the successive walls which encompassed the town and the acropolis. The inner city wall, which was the first in date (it was probably built in the thirteenth century), is provided with rectangular towers which have a salience of 2 metres. The outer acropolis wall (Fig. 5), built about 900 B.C., has semicircular towers with a salience of 3½ metres; the strategic disadvantages of rectangular towers had been realized and corrected. A further improvement was effected in the inner cross wall, behind the main gate of the acropolis. The wall is built in retreating angles, and set with towers alternately rounded and rectangular; the rectangular towers project 1·80 metres from the face of the wall, while the rounded towers cover them with a projection of 4·50 metres. The outer city wall was built after the destruction of the city by Asarhaddon in 681 B.C. and is no more than a copy of the earliest wall, but at the same period casemates were added to the walls of the acropolis.[220] The Hittite capital of Qadesh on the Orontes, as depicted in the frescoes at Abû Simbel, a temple built by Rameses II (1388-1322), was protected by a wall with towers, the height of which must be due partly to the imagination of the Egyptian craftsman.[221] These towers have the appearance of being round, but the absence of architectural records of round towers at so early a date throws doubt upon the matter. In Asia Minor rectangular towers have been found upon the outer and the inner walls of Boghâz Keui;[222] they do not as a rule exceed a projection of 2½ metres. At Troy the earliest walls had towers 3 metres wide, and 2 metres salient; the curtain wall was in some places not longer than 10 metres, and the city gates were flanked by deep bastions. In the walls of the third period at Troy three towers were uncovered on the south-east side; they are 3·20 metres wide, 2·35 salient, and are separated from one another by a distance of only 6·40 metres.[223] But on the Greek mainland, at Tiryns, and at Mycenae, the fortifications are characterized by crémaillères and by deep bastions rather than by towers.[224] Much more lavish is the use of towers in the