Some good points so far

If you study Assyrian warfare you will notice the steady shift to cavalry starting from 900-850 BC. Constant warfare with Urartu - a mighty kingdom in the mountains near Lake Van - initiated the change. They were in close contact with the Cimmerians and Iranian horsetribes in the north and east, and were famous in Assur for their horses.

A Cimmerian (or Scythian?) army showed the King from Urartu clearly just how brutal masses of highly mobile horsearchers are against the fewer, less mobile missileplatforms of old, inflicting them a massive crushing defeat, which was reported by spies back to the assyrian King. So they and the Assyrians tried all they could to get good cavalry horses which could carry a men. After a hundred years armored horsemen with long spears sitting on good horses with armor started to show up...


One could also talk about chinese chariot warfare, however my time is running out...