The young Caesar was then established in Sirmium to represent the Licinius family in the government of the troubled Illyrian provinces, while Gallienus transferred his attentions to Germany to deal with barbarian incursions into Gaul.

[4] Although she could not publicly dispute the decisions of Valerian, the pater patriae which had been formally agreed by her husband, Gallienus, she suspected Ingenuus's motives and asked an officer called Valentinus, otherwise unknown, to keep an eye on him.

It seems to show that the mere presence of a member of the Imperial House in a troubled region was not sufficient to assuage local fears of being neglected by the distant Emperor.

The local Caesar had to wield undisputed authority in his region and command the resources and the experience to deal with the internal and external threats to its security.

Diocletian and Maximian seem to have understood this when they set up Constantius Chlorus and Galerius as Caesars in Gaul and Illyria respectively some thirty-five years later.