Editing Grand duke (section)

===Byzantine grand dukes===
{{Further|Megas doux}}
The Latin title ''[[dux]]'' (the etymological root of [[duke]]), which was phonetically rendered ''doux'' (δούξ) 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]]).

Under the latter, exclusively Byzantine [[Theme (Byzantine district)|theme system]], the commander of a theme was often styled a ''doux'' instead of the earlier ''[[strategos]]'' from the 10th century on. The title of "Grand Duke" (''megas doux'') was created by [[Alexios I Komnenos]] and was conferred upon the commanding admiral of the [[Byzantine navy]]. As such, it was an actual office rather than a court rank (although it also became a grade in the court order of precedence under the [[Palaiologan era|Palaiologan emperors]]), and was always held by one individual.