Batavi (military unit)

The Batavi was an auxilia palatina (infantry) unit of the Late Roman army, active between the 4th and the 5th century. It was composed by 500 soldiers and was the heir of those ethnic groups that were initially used as auxiliary units of the Roman army and later integrated in the Roman Empire after the Constitutio Antoniniana. Their name was derived from the people of the Batavi.

In the sources they are usually recorded together with the Heruli, and it is probable the two units fought together.

At the beginning of the 5th century two related units are attested, the Batavi seniores and the Batavi iuniores.

The Batavi belonged to the army of the Caesar Julian, and fought in the Battle of Strasbourg (357). Deployed in the second line, together with the Regii, the Batavi sustained the assault of the outnumbering Alamannic infantry, which had broken the Roman first line. Pushed back until the hill where the Roman camp had been built, the Batavi were reinforced by the camp guards and repulsed and broke the enemy.

In 360, before Julian received the order of sending most of his troops to emperor Constantius II of a campaign in the East, the Batavi, the Heruli and two numeri Moesiacorum were sent in Britain under the command of Lupicinus, Julian's magister militum, probably to counter a rebellion. Later the Batavi and the Heruli returned on the continent, but it is unknown when this happened.

The Emperors Valentinian I and Valens divided the army among themselves. Many units were divided into two sub-units, sharing the name of the original unit and each distinguished by the name seniores, for the units of the senior Augustus Valentinian, and iuniores, for the units of the iunior Augustus Valens, and aggregated respectively to the Western Roman army and to the Eastern Roman army.

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