The army was made an irresistible engine of attack.  Its training, discipline, and arms were such as the world had never seen before.  And the army was followed by a body of administrators.  The conquered population was transported elsewhere or else deprived of its leaders, and Assyrian colonies and garrisons were planted in its place.  The administration was intrusted to a vast bureaucracy, at the head of which stood the king.  He appointed the satraps who governed the provinces, and were responsible for the taxes and tribute, as well as for the maintenance of order.  The bureaucracy was partly military, partly civil, the two elements acting as a check one upon the other.

But it was necessary that Ararat should be crushed before the plans of the new monarch could be carried out.  The strength of the army was first tested in campaigns against Babylonia and the Medes, and then Tiglath-pileser marched against the confederated forces of the Armenian king.  A league had been formed among the princes of northern Syria in connection with that of the Armenians, but the Assyrian king annihilated the army of Ararat in Comagene, and then proceeded to besiege Arpad.  Arpad surrendered after a blockade of three years; Hamath, which had been assisted by Azariah of Judah, was reduced into an Assyrian province; and a court was held, at which the sovereigns of the west paid homage and tribute to the conqueror (B.C. 738).  Among these were Rezon of Damascus and Menahem of Samaria.  Tiglath-pileser was still known in Palestine under his original name of Pul, and the tribute of Menahem is accordingly described by the Israelitish chronicler as having been given to Pul.

The Assyrian king was now free to turn the full strength of his forces against Ararat.  The country was ravaged up to the very gates of its capital, the modern Van, and only the strong walls of the city kept the invader out of it.  The Assyrian army next moved eastward to the southern shores of the Caspian, striking terror into the Kurdish and Median tribes, and so securing the lowlands of Assyria from their raids.  The affairs of Syria next claimed the attention of the conqueror.  Rezon and Pekah, the new king of Samaria, had attempted to form a league against Assyria; and, with this end in view, determined to replace Ahaz, the youthful king of Judah, by a creature of their own.  Ahaz turned in his extremity to Assyrian help, and Tiglath-pileser seized the opportunity of accepting the vassalage of Judah, with its strong fortress of Jerusalem, and at the same time of overthrowing both Damascus and Samaria.  Rezon was closely besieged in his capital, while the rest of the Assyrian army was employed in overrunning Samaria, Ammon, Moab, and the Philistines (B.C. 734).  Pekah was put to death, and Hosea appointed by the Assyrians in his place.  After a siege of two years, Damascus fell in B.C. 732, Rezon was slain, and his kingdom placed under an Assyrian satrap.  Meanwhile Tyre was compelled to purchase peace by an indemnity of 150 talents.