Babylon, and attempting to inflict on her the fate they had brought upon Nineveh.  Nebuchadrezzar, therefore, was anxious to interpose, between himself and these possible foes, such a series of fortifications that the most persevering enemy would be worn out by the prolonged task of forcing them one after another, provided that they were efficiently garrisoned.  He erected across the northern side of the isthmus between the two rivers a great embankment, faced with bricks cemented together with bitumen, called the Wall of Media; this wall, starting from Sippara, stretched from the confluence of the Saklauiyeh with the Euphrates to the site of the modern village of Jibbara on the Tigris; on both sides of it four or five deep trenches were excavated, which were passable on raised causeways or by bridges of boats, so arranged as to be easily broken up in case of invasion.

[Illustration:  456.jpg CITY DEFENDED BY A TRIPLE WALL]

     Drawn by Faucher-Gudin, from a bas-relief of the time of
     Sargon, in the Museum of the Louvre.

The eastern frontier was furnished with a rampart protected by a wide moat, following, between Jibbara and Nipur, the contours of a low-lying district which could be readily flooded.  The western boundary was already protected by the Pallakottas, and the lakes or marshes of Bahr-i-Nejif:  Nebuchadrezzar multiplied the number of the dikes, and so arranged them that the whole country between the suburbs of Borsippa and Babylon could be inundated at will.  Babylon itself formed as it were the citadel in the midst of these enormous outlying fortifications, and the engineers both of Nabopo-lassar and of his son expended all the resources of their art on rendering it impregnable.  A triple rampart surrounded it and united it to Borsippa, built on the model of those whose outline is so frequently found on the lowest tier of an Assyrian bas-relief.

[Illustration:  457.jpg PROBABLE SECTION OF THE TRIPLE WALL OF BABYLON]

     Reproduced by Faucher-Gudin, from the restoration by
     Dieulafoy.

A moat of great width, with banks of masonry, communicating with the Euphrates, washed the foot of the outer wall, which retained the traditional name of Imgur-bel:  behind this wall rose Nimitti-bel, the true city wall, to a height of more than ninety feet above the level of the plain, appearing from a distance, with its battlements and towers, more like a mountain chain than a rampart built by the hand of man; finally, behind Nimitti-bel ran a platform on the same level as the curtain of Imgur-bel, forming a last barrier behind which the garrison could rally before finally owning itself defeated and surrendering the city.  Large square towers rose at intervals along the face of the walls, to the height of some eighteen feet above the battlements:  a hundred gates fitted with bronze-plated doors, which could be securely shut at need, gave access to the city.*