the phalanx usually advanced at a walking pace, although it is possible that they picked up speed during the last several yards. one of the main reasons for this slow approach was to maintain formation. the formation would be rendered useless if the phalanx was lost as the unit approached the enemy and could even become detrimental to the advancing unit, resulting in a weaker formation that was easier for an enemy force to break through. if the hoplites of the phalanx were to pick up speed toward the latter part of the advance, it would have been for the purpose of gaining momentum against the enemy in the initial collision. herodotus states of the greeks at the battle of marathon, that "they were the first greeks we know of to charge their enemy at a run". many historians believe that this innovation was precipitated by their desire to minimize their losses from persian archery. the opposing sides would collide, possibly severing many of the spears of the row in front and killing the front part of the enemy army due to the bone-breaking collision.