Megas droungarios tes viglas

The Droungarios of the Watch (Greek: δρουγγάριος τῆς βίγλης/βίγλας, droungarios tēs viglas/viglēs), sometimes anglicized as "Drungary of the Watch", was originally a senior Byzantine military post. Attested since the late 8th century, the droungarios commanded the Vigla or "Watch", one of the elite professional cavalry regiments (tagmata) of the middle Byzantine period, and was in charge of the Byzantine emperor's personal security. From ca. 1030, the office was disassociated from its military origin and was transformed into a senior judicial position, thereafter usually referred to as the Grand Droungarios of the Watch (μέγας δρουγγάριος τῆς βίγλης/βίγλας, megas droungarios tēs viglas/viglēs). The office continued to exist as a mostly honorific court dignity in the Palaiologan era, until the very end of the Byzantine Empire in the mid-15th century.

The Droungarios of the Watch was originally the commander of the Vigla ("guard watch") or Arithmos ("number"), the third of the tagmata, professional cavalry regiments headquartered in and around Constantinople, and distinct from the provincial or thematic troops. The title of droungarios itself means "commander of a droungos", a term of Gaulish origin which came to be used as a term for a kind of tactical cavalry formation in the East Roman army of Late Antiquity. The term droungarios (Greek: δρουγγάριος) is not documented before the early 7th century but might have been used as an informal or unofficial designation before that date. The office and the corresponding unit appear to have initially referred to ad hoc arrangements, but during the early 7th century these were formalized, like much of the East Roman army's rank structure.

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