In a nutshell, while the phalanx had a very powerful frontal attack, it was also very susceptible to flanking.

The Hoplite Phalanx was most vulnerable when facing lighter, more flexible troops without proper support. This was demonstrated in the Battle of Lechaeum, where Athenian missile troops caused disarray among Spartan hoplites. The Macedonian Phalanx shared similar weaknesses, being nearly indestructible from the front but vulnerable at its flanks and rear. It required protection on its flanks from more mobile infantry or cavalry.

The phalanx could lose cohesion if not properly coordinated or if moving through broken terrain, making it susceptible to attacks by more flexible units like Roman legions. The psychological readiness of hoplites to replace fallen soldiers in the front ranks was crucial for the phalanx's strength. Most phalanx-centric armies lacked supporting echelons, so breaking through the line or compromising a flank often ensured victory for the opposing force.
spam fails_task lang_mismatch pii not_appropriate hate_speech sexual_content quality toxicity humor helpfulness creativity violence