74 A History of Art in Ciiald.ea and Assyria. see a long band of prisoners of both sexes being led off by soldiers. These we may suppose to be captives taken in the suburbs of the beleaguered city, or in battles already won. 1 The Assyrians not only understood how to defend their own cities, and to destroy those of their foes, they were fully alive to the necessity for good carriage roads, if their armies and military machines were to be transported rapidly from place to place. How far these roads extended we do not know, but Place ascer- tained the existence of paved causeways debouching from the Fig. 29. — Siege of a fort ; from Layard. gates of Dour-Saryoukin, 2 and unless they stretched at least to the frontiers, it is difficult to see how the Assyrians could have made such great use as they did of war chariots. Not one of 1 It is even believed that the Assyrians used a machine for launching great stones, like the Roman catapult. The representations in the bas-reliefs are not, however, very clear. Rawlinson, The Five Great Monarchies, vol. i. p. 472. 2 Place, Ninive, vol. i. p. 196. Causeways of this kind may be noticed stretching away from the tower in our Fig. 29. See also Layard, Monuments, 2nd series, plates 18 and 21.