==Sources==* Mennen, Inge, "Power and Status in the Roman Empire, AD 193-284" (2011)* Pat Southern, "Roman Empire from Severus to Constantine", Routledge, 2001, ISBN 0-203-45159-7, pp.
* Pat Southern, Roman Empire from Severus to Constantine, Routledge, 2001, ISBN 0-203-45159-7, pp.