A phalanx was a type of?

A phalanx was a type of Greek squad of soldiers. Each soldier carried a round shield and a spear. The phalanx was a square of soldiers. Phalanxes were extremely vulnerable from attack on the flanks and rear. They were used mostly to break the front of an army. Since each soldier carried roughly fifty extra pounds of weight in armor and weapons, the phalanx moved slowly. They could also not pursue enemy troops if they decided to flee. They walked towards the enemy soldiers and just before impact starting running, giving some momentum to their charge. If a soldier in the front line fell, ones in the back pressed forward and took their place. It was advantageous for a phalanx to attack from high ground, which lent more momentum to a charge.