Grand Duke - Byzantine Grand Dukes

Byzantine Grand Dukes

The Latin title dux (the etymological root of duke), which was phonetically rendered δουξ in Greek, was a common title for imperial generals in the Late Roman Empires (west and east), but note it was lower in rank than Comes (the etymological root of Count). In the Eastern Empire, a dux ranked just below a strategos.

Under the latter, exclusively Byzantine theme system, the commander of a theme was often styled a dux. The title of "Grand Duke" (megas doux) was created by Alexios I Komnenos and was conferred upon the commanding admiral of the Byzantine navy. The title remained in use until the Empire's end, by which time the office had become a virtual chief minister, heading both civil and military administration.