*Maximian co-emperor, 286 A. D.* One of the first acts of Diocletian was to coöpt as his associate in the _imperium_, with the rank of Caesar, a Pannonian officer named Valerius Maximianus. In 286 Maximian received the title of Augustus and equal authority with Diocletian. However, the latter always dominated his younger colleague, and really determined the imperial policy. In conformity with the undisguised absolutism of his rule, Diocletian assumed the divine title of Jovius, and that of Herculius was bestowed upon Maximian. Diocletian’s choice of a co-emperor was determined largely by the conviction that the burden of empire was too heavy to be borne by one man. He therefore entrusted the defense of the western provinces to Maximian, while he devoted his attention to the Danubian and eastern frontiers. Maximian’s first task was to quell a serious revolt of the Gallic peasants, called Bagaudae, occasioned by the exactions of the state and the landholders. After crushing this outbreak (285 A. D.), he successfully defended the Rhine frontier against the attacks of Franks, Alamanni and Burgundians (286–88 A. D.). However, in the meantime a usurper had arisen in Carausius, an officer entrusted with the defense of the Gallic coast against the North Sea pirates, who made himself master of Britain and proclaimed himself Augustus (286 A. D.). Maximian was unable to subdue him, and the two emperors were forced against their will to acknowledge him as their colleague. *Regulation of the succession.* Diocletian saw in the absence of a strict regulation of the succession a fertile cause of civil strife. To do away with this, and to discourage the rise of usurpers, as well as to relieve the Augusti of a part of their military and administrative burdens, he determined to appoint two Caesars as the assistants and destined successors of Maximian and himself. His choice fell upon Gaius Galerius and Flavius Valerius Constantius, both Illyrian officers of tried military capacity. They received the title of Caesar on 1 March, 293 A. D. To cement the tie between the Caesars and the Augusti, Diocletian adopted Galerius and gave him his daughter in marriage, while Maximian bound Constantius to himself in the same way. It was the plan of Diocletian that the Augusti should voluntarily abdicate after a definite period, and be succeeded by the Caesars, who in turn should then nominate and adopt their successors.