Macedonian Phalanx - Drawbacks

Drawbacks

The armies of the early Hellenistic period were equipped and fought mainly in the same style as Alexander's. Towards the end, however, there was a general slide away from the combined arms approach back to using the phalanx itself as the arm of decision, having it charge into the enemy lines much like earlier hoplites had. This left the formation fairly vulnerable — though near invincible to forwards assault, phalanxes like other infantry formations were fairly prone to flanking, and worse still tending to break up when advancing quickly over rough ground. So long as everyone was using the same tactics these weaknesses were not immediately apparent, but with the advent of the Roman legion they proved fatal in every major engagement, the most famous being the Battle of Pydna, as the Romans were able to advance through gaps in the line and easily defeat the phalangites once in close.