Nebuchadrezzar no longer found any rival to oppose him save the king of Assyria, whom he attacked; but now his aggression was checked, for though his forces were successful at first, they were ultimately sent flying across the frontiers with great loss, through the prowess of Assurishishi, who became a mighty king in Nineveh. But his son, Tiglath-pileser, is the first of the great warrior kings of Assyria to stand out before us with any definite individuality. He immediately, on his accession, began to employ in aggressive wars the well-equipped army left by his father, and in three campaigns he regained all the territories that Shalmaneser I. had lost, and also conquered various regions of Asia Minor and Syria. In a rising of the Chaldæans he met with a severe defeat, which he did not long survive, dying about the year 1100 B.C. There is only one gleam in the murky night of this period. A certain Assurirba seems to have crossed Northern Syria, and, following in the footsteps of his great ancestor, to have penetrated as far as the Mediterranean; on the rocks of Mount Amanus, facing the sea, he left a triumphal inscription in which he set forth the mighty deeds he had accomplished. His good fortune soon forsook him. The Arameans wrested from him the fortresses of Pitru and Mutkinu, which commanded both banks of the Euphrates near Carchemish. What were the causes of this depression from which Babylon suffered at almost regular intervals, as though stricken with some periodic malady? The main reason soon becomes apparent if we consider the nature of the country and the material conditions of its existence. Chaldæa was neither extensive nor populous enough to afford a solid basis for the ambition of her princes. Since nearly every man capable of bearing arms was enrolled in the army, the Chaldæan kings had no difficulty in raising, at a moment's notice, a force which could be employed to repel an invasion, or to make a sudden attack on some distant territory; it was in schemes that required prolonged and sustained effort that they felt the drawbacks of their position. In that age of hand-to-hand combats, the mortality in battle was very high; forced marches through forests and across mountains entailed a heavy loss of men, and three or four campaigns against a stubborn foe soon reduced the army to a condition of weakness. When Nebuchadrezzar I. made war on Assurishishi, he was still weak from the losses he had incurred during the campaign against Elam, and could not conduct his attack with the same vigour as had gained him victory on the banks of the Ulai. In the first year he only secured a few indecisive advantages; in the second he succumbed.