=Campaigns Against the Moabites and Ammonites.= The Moabites, who, during the period of settlement, had pushed forward to the fords of the Jordan, were apparently the first to be attacked and to become subject to David. The Ammonites, recognizing the significance of the new west-Jordan power, assumed the initiative and insulted David's messengers. To aid them in the conflict they called in certain of the Aramean princes in the north. After the downfall of the old Hittite kingdom these Aramean peoples had pressed in from the northeast and taken possession of the greater part of central and eastern Syria. The desert highway that ran through the Ammonite capital led northward through these Aramean states and thus established a close commercial and political bond between the two peoples. The Arameans, living on the plains and in close touch with the most advanced civilization of the Semitic world, were possessed of chariots and all the equipment of ancient warfare. In these allied forces, therefore, the armies of David met no mean foes; but in the school of constant and strenuous warfare he had developed a strong fighting force, and in Joab he possessed one of the best generals of the age. =Situation of Rabbath-Ammon.= The decisive battles of this campaign were fought near or in Rabbath-Ammon. The city was surrounded by rolling plains, especially on the west, which offered ample opportunity for the manœuvring of armies. The strength of the city itself consisted in its huge acropolis, surrounded, like Jerusalem, by deep valleys. On the north it was connected with the surrounding hills by a low, narrow neck of rock. At this point were built great protecting walls and towers. The hill itself consisted of three terraces rising from east to west, with a main gateway on the south side. Each of the succeeding terraces was defended by a wall. The highest area, which included several acres, rose nearly three hundred feet above the surrounding valleys, and it was, therefore, the largest and in many ways the strongest natural fortress in all Palestine. =The Water City.= The Water City,^{(96)} which was first captured by Joab, was probably in the valley of the Jabbok, which runs along the southern side of the acropolis. This valley, and that which comes in from the north along the western side of the acropolis, is the site of the modern city of Amman. The great Roman city was also built for the most part in the Valley of the Jabbok, or, as it is now called, the Wady Amman. Here the waters of the brook, which were carried by aqueducts along different levels and which were supplemented by gushing springs, fully justify the name of Water City. Situated in the valley, it was most exposed to the attack of the Hebrews. When it was captured, the supply of water and food would be cut off from the citadel above, so that, as indicated by the biblical narrative, the fall of the entire city would be the inevitable result of a long siege.