How did ancient warfare blend into a transition to medieval warfare?

Answer 1

The weapons were similar, the motives were similar, and the terms ancient and mediaeval are merely modern words we use to describe eras before and after the magic year 500 CE, which is jist a number picked out of the air roughly coinciding with the demise of the western Roman Empire and the dramic drop in civilisation after the barbarian invaders took over.

Answer 2

Ancient warfare slowly blended into medieval warfare. It was not a one step process. Part of the way was based on the alterations that took place as the Roman military faced the challenges faced by the onslaught of barbarians on the Roman frontiers with Europe. Within the Roman army, the strengthening of the cavalry was done to deal with these enemies.The barbarian flexibilities posed a threat to Roman legion flanks and rear guard. Roman solutions were based on a mobile and heavily mounted force. By 300 AD, Roman consuls were forced to make changes to the extent that they resembled the armies of Alexander the great.

Heavily armored legions were observed by barbarian military leaders. When Rome's power in the West began to vanish, their previously successful military style was adopted by Rome's enemies and the now new medieval "powers" had an uncanny resemblance the the last stages of Roman power.