Assyria was unstrategically located. Between it and Akkad to the south was a plain where no invader could possibly be stopped except by stronger forces. The precipitous Zagros range to the east and the formidable Armenian plateau to the north, both sloping towards Assyria, made attack from those dimensions easy but defense difficult. The western steppe was no effective barrier either, for it was easy for a foe to traverse as for Assyrians. In its early history, and intermittently afterwards, Assyria was therefore ruled by foreign invaders.

There was only one means to overcome these geographical handicaps, a strong army. Assyria therefore proceeded to build up the most powerful military machine the world had yet seen, and to use it not only for defense but for expansion abroad. But unlike the Roman legions, which were formidable even when led by mediocrities, the Assyrian army depended for victory on brilliant generals, so that Assyrian power depended on the prowess of the king.

The army relied mainly upon archers and pikemen, some very lightly armored, some protected by a cuirass and a conical helmet, and carrying a short sword for close fighting. Coordinated with this infantry was the cavalry, which at first fought from chariots. Later on, when the warrior rode the horse (about 700 [B.C.E.]), he had the infantryman's bow and spear. Still later came the most original Assyrian contribution to the art of warfare, siege artillery. No fortified city could withstand the assault of Assyrian engines. A choice body of troops fought beside the king, but it was the foot-bowmen who wrought havoc on the enemy.

The Assyrian army's power cannot be entirely explained by the bravery of the individual soldier, the competence of the king-general, or the sheer numerical strength so easy to attain in a country where every able-bodied man was subject to military service. Perhaps it is better explained by the theory that the Assyrians used iron extensively. Indeed something like a revolution in the metal industry apparently took place under Sargon II (722-705 [B.C.E.]) when he invaded Urartu and exploited its iron mines. Cunning, too, aided Assyrian armies: an efficient espionage and intelligence service was conducted by the royal governors and bureaucrats in the provinces and centered in the king's palace. Frequently when the troops entered a country they were aided by carefully organized fifth columns.