Editing Dux (section)

===Diocletian's reforms===

Under Diocletion, during the [[Tetrarchy]], a new office called ''dux'' was created with powers split from the role of the governor of a province. The dux was the highest military office within the province and commanded the legions, but the governor had to authorise the use of his powers after which the ''dux'' could act independently and handle all military matters.{{cn|date=June 2024}} The ''[[Dux Belgicae secundae]]'' ("commander of the second Belgic province") is an example.

Also the provinces were reorganised into [[Roman diocese|dioceses]] with each diocese administered by a [[vicarius]]. As with the governors, the vicarius was assisted by a ''dux''. This ''dux'' was superior to all other ''duces'' within the dioceses; when the vicarius called the legions of the dioceses into action, all of the legions were at the command of the ''dux''.{{cn|date=June 2024}} The office of ''dux'' was, in turn, made subject to the [[magister militum]] of his respective [[praetorian prefecture]], and above him to the [[Roman Emperor|emperor]]. The ''Dux per Gallias'' of the diocese of [[Gaul]] is an example of this office.