- Source: Biarchus
A Biarchus was a military position in the army of the Late Roman Empire. It was created after the military reforms of Diocletian. They are found throughout a variety of military positions in the Roman military. The Code of Justinian mentions the position of Biarchus as part of the Agentes in Rebus, which were the Imperial couriers. The name Biarchus is also found in the scholae palatina, auxilia palatina, fabricae, vexillationes, and in the stratores. Their duties are unknown, but they may have related to food supply. The biarchus was subordinate to the centenarius and the ducenarius but above the circitor in the command structure of the Roman military. This position replaced the role of the Optio.
It is possible that the Biarchus commanded a contubernium, which was a Roman military unit consisting of ten men. Historian Michael Speidel argued that Roman texts on military formations and ancient inscriptions indicate that in the Late Roman military the biarchus was synonymous with the decanus, who commanded the contubernium. He cites Maurice's Strategikon, which claims that soldiers who ate and slept together fought in a file together. An ancient Roman inscription mentions a figure named Flavius Iovianus, who is said to a biarchus draconarius. The draconarius was a standard-bearer in the Roman military. Speidel argues, citing Maurice, that the standard bearer also served as the file leader. Henceforth, Speidel concludes that Iovianus also served as a file leader, and the title of biarchus references this role. Speidel cites Vegetius, who called the mess-leader the caput contubernii. The biarchus also had the role of mess-leader in the Late Roman army. Vegetius claims that this mess-leader had the same role as the decanus. Historian Warren Treadgold argued that Biarchus also held the same powers as a decurion.
Speidel also proposed that the rank of Biarchus derived from the rank of exarchus. He argued that soldiers could earn the title of Bis Exarchus, and that this title was shortened to Biarchus. Speidel cited an inscription which rewarded soldiers with the title Bis exarchi. According to Speidel, this theory provides an explanation as for why the title of exarchus is primarily used in the third century, whilst the title of Biarchus is used throughout the fourth and fifth centuries. Speidel states that the Greek etymology of the word exarchus implies the position has eastern roots and potentially originated from new units being created from preexisting horseman and decurions.
The position is mentioned in the text Ad Pannachium by Saint Jerome. Saint Jerome listed officer ranks in the Roman army, including those of the biarchus. In the Codex Theodosianus it is stated that no one is allowed to achieve the rank of Biarchus through patronage. Instead, it mandates that an individual must achieve the rank through merit. The code prohibits more than 250 Biarchi serving on duty. Furthermore, the code mandates that if a Biarchus or anyone of a lower rank dies in battle, then their son is obligated to take their place in the army and earn their pay. One edict issued in the year 534 found in the Code of Justinian directed towards Belisarius outlines the annual payment of eight Biarchi in Africa. It decrees that each of the Biarchi was to be given 14 solidi in payment.