the decline of the diadochi and the phalanx was inextricably linked with the rise of rome and the roman legion from the 3rd century bc. before the battle of the caudine forks, where the clumsiness of the roman phalanx was displayed by the samnites (the romans had originally employed the phalanx themselves) but gradually evolved more flexible tactics resulting in the three-line roman legion of the middle period of the roman republic. the phalanx continued to be employed by the romans as a tactic for their third military line or "triarii" of veteran reserve troops armed with the "hastae" or spear. rome would eventually conquer most of the macedonian successor states, and the various greek city-states and leagues. these territories were incorporated into the roman republic, and as these hellenic states had ceased to exist, so did the armies which had used the traditional phalanx formation. subsequently, troops raised from these regions by the romans would have been equipped and fought in line on the roman model.