 Extended Gradualists argue that hoplite warriors did not fight in a true phalanx until the 5th century BC.Making estimations of the speed of the transition reached as long as 300 years, from 750–450 BC.The exact time when hoplite warfare was developed is uncertain, the prevalent theory being that it was established sometime during the 8th or 7th century BC, when the "heroic age was abandoned and a far more disciplined system introduced" and the Argive shield became popular.