The Macedonian Phalanx is a military formation of armored pikemen that first saw widespread use in the armies of Alexander the Great, as well as in the Diadochi kingdoms following the breakup of his empire.
While the armor worn by phalangites or pikemen varied greatly throughout classical antiquity, their main weapon was typically a sarissa or xyston 21 feet in length. Phalangites marched in formations of between eighty and three hundred men in rows four to twelve men deep and arranged in such a manner as to present a wall of spearpoints toward the enemy.
The Macedonian phalanx is distinguished from the hoplite phalanxes by their longer spears, heavier armor and tighter formations, affording a superior projection of force on the battle line at the cost of greatly reduced flexibility and speed. Tactically, one should never expect to beat a phalanx from the front, except of course with another phalanx.