Batavi ( military unit ) The Batavi was an " auxilia palatina " ( light 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 . History . " Batavi " . 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 were 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 . " Batavi seniores " and " iuniores " . 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 . In 365 , when Emperor Valentinian I ( 364 - 375 ) had to confront the invading Germans and was defeated in battle , the inquires found that the " Batavi " ( " seniores " ) had been the first to flee . Before the whole army , Valentinian put the shame on the Batavi , and ordered to strip them of their arms and to sold them as runaway slaves . The soldiers of the legion bowed to the Emperor begging him to forgive them and give them an opportunity to redeem themselves and , at his invitation , took up arms , left the camp and attacked the enemies , killing the great part of them . It happened too ( it is unclear whether at this time or not ) that the barbarians were able to subtract the banner of the " Batavi " and " Heruli " units , which were made the object of derision by the raiders . In 367 - 369 there was a revolt in Britain against Valentinian I , known as Great Conspiracy and put down by the later emperor Theodosius I . In this occasion , both the " Batavi " and the " Heruli " were sent to Britain along with " Iovii " and " Victores " . They landed at Richborough and headed for London . The " Batavi " ( probably " iuniores " ) also took part in one of the most significant battles of antiquity , the Battle of Adrianople ( 378 ) , during which they were deployed in the reserve . When the " magister equitum " Victor joined them on the orders of Emperor Valens to start a desperate resistance , he discovered that they had already fled . The " Notitia Dignitatum " , a document prepared in the years 400 - 420 , shows the deployment of the " Batavi seniores " and of the " Batavi iuniores " . The " Batavi seniores " are listed both under the command of the " Magister militum praesentalis " in the East and under that of the " Magister peditum " for Italy in the West . The " Batavi iuniores " are listed under the command of the " Magister peditum " for Italy , but they were probably sent to reinforce the army of Gaul , since they are also under the " Magister equitum " of Gaul .