Excubitors

The Excubitors ( or , , i.e. 'sentinels'; transcribed into Greek as , ) were founded in as an imperial guard-unit by the Roman emperor Leo I the Thracian. The 300-strong force, originally recruited from among the warlike mountain tribe of the Isaurians, replaced the older as the main imperial bodyguards. The Excubitors remained an active military unit for the next two centuries, although, as imperial bodyguards, they did not often go on campaign. Their commander, the Count of the Excubitors (, ), soon acquired great influence. Justin I was able to use this position to rise to the throne in 518, and thereafter the Counts of the Excubitors were among the main political power-holders of their day; two more, Tiberius II Constantine and Maurice, rose to become emperors in the late 6th century.

In the later part of the 7th century the Excubitors appear to have morphed into a parade-ground formation, and they fade from the record as a corps. Individual seals of office suggest that the title of became an honorific dignity rather than an active military appointment during the early part of the 8th century. This changed , when the Emperor Constantine V reformed the corps into one of the élite – professional heavy-cavalry regiments that constituted the core of the Byzantine army of the middle-Byzantine period. Notable members of the regiment during this time include Saint Joannicius the Great (served to 792), and Emperor Michael II the Amorian, who served as regimental commander, or Domestic of the Excubitors (), before rising to the throne in 820. The Excubitors fought in several campaigns during the following centuries, and are last attested in the disastrous Battle of Dyrrhachium in 1081 that destroyed the remnants of the middle-Byzantine army.