The decline of the Diadochi and the phalanx was linked with the rise of Rome and the Roman legions from the 3rd century BC. The Battle of the Caudine Forks showed the clumsiness of the Roman phalanx against the Samnites. The Romans had originally employed the phalanx themselves but gradually evolved more flexible tactics. The result was the three-line Roman legion of the middle period of the Roman Republic. Romans used a phalanx for their third military line, the "triarii". These were veteran reserve troops armed with the "hastae" or spear. Rome conquered most of the Macedonian successor states. Also the various Greek city-states and leagues. As these states ceased to exist, so did the armies which used the traditional phalanx. Subsequently, troops from these regions were equipped, trained and fought using the Roman model.