 Maximian was only disturbed from his rest in 303 by Diocletian 's vicennalia , the 20 @-@ year anniversary of his reign , in Rome . Some evidence suggests that it was then that Diocletian exacted a promise from Maximian to retire together , passing their titles as Augusti to the Caesars Constantius and Galerius . Presumably Maximian 's son Maxentius and Constantius ' son Constantine – children raised in Nicomedia together – would then become the new Caesars . While Maximian might not have wished to retire , Diocletian was still in control and there was little resistance . Before retirement , Maximian would receive one final moment of glory by officiating at the Secular Games in 304 . 
