A
phalanx is a rectangular array of
infantry, typically
spearmen or
pikemen.
The formation was typically close order so the weapons could be used to keep enemies at a distance.
The first phalanxes appear on
Sumerian inscriptions, and they dominate the battlefield for millennia, reaching their culmination in the
Macedonian phalanx under
Alexander the Great and his successors.
Phalanxes are generally good on forward defense, but have difficulty advancing and are weak on the flanks.
They were largely replaced by the much more mobile
Roman legion, though phalanxes of pikemen were employed against mounted
knights with considerable success.