Dux

Dux (plural: duces) is Latin for leader (from the verb ducere, 'to lead') and could refer to anyone who commanded troops, such as tribal leaders.

[edit] Roman empire

In the Roman military, a Dux would be a general in charge of two or more legions. While the title of dux could refer to a Consul or Imperator, it usually refers to the Roman Governor of the provinces. As the governor, the dux was both the highest civil official as well as the commander-in-chief of the legions garrisoned within the province.

However, during the time of the Dominate, the powers as a dux were split from the role of the governor and were given to a new office called "Dux". The dux was still the highest military office within the province and commanded the legions, but the governor had to authorise the use of the dux's powers. But once authorised, the dux could act independently from the governor and handled all military matters. An example would be the Dux per Gallia Belgica which was the Dux of the province of Gallia Belgica.

Since Diocletian's Tetrarchy reform, the provinces were organized into dioceses each administered by a Vicarius. As with the Governors, the Vicarius was assisted by a Dux. This Dux was superior to all of other Duces within the dioceses and when the Vicarius called the legions of the dioceses into action, all of the legions were at the Dux's command. An example would be the Dux per Gallia which was the Dux of the Dioceses of Gaul. The office of Dux was, in turn, made subject to the Magister Militum of his respective Praetorian prefecture, and above him to the Emperor.

In the Byzantine empire, the hellenized form doux (same pronunciation) came into use.

[edit] Post-Roman uses

Dux (genitive ducis) is also the root of various high feudal noble titles of peerage rank, such as (via the French duc) the English duke, and their derivatives, e.g. the Italian doge and Duce, the modern Greek ducas (δούκας). In Italy's Fascist era, Prime Minister Benito Mussolini was known as "Il Duce", a term derived from "Dux".

In English and other languages, dux is also a modern title given to the top academic student in a graduating class of a school, used in Scotland, Australia, New Zealand and Iceland, similar to the American concept of a valedictorian; compare also dean's list.