Why did the Assyrian state become the most powerful state?

Not far from the source of the Tigris, in the mountains and foothills, there were large deposits of iron ore. The Assyrians mastered the smelting of iron, although its processing requires higher temperatures than copper. But iron weapons are stronger than copper ones. They also bred a new breed of horses adapted for riding, and were the first to acquire cavalry in their army. They used mobile towers and battering rams to siege cities.