Batavia (region) in the context of "Salian Franks"

The Batavians or Batavi were a Roman-era Germanic people that lived in Batavia in the eastern Rhine delta — an area that is now the Netherlands, but then lay upon the northernmost border of the Roman Empire in continental Europe. Their origins are uncertain, but they appear to have settled in Batavia around 50–15 BC, when a Rome-allied Chatti military elite joined a Celtic-influenced community that had already been living there long before the arrival of the Romans. Throughout the several centuries in which they appear in historical records the Batavians were continually associated with elite cavalry units in the Roman military, who were famous for their ability to cross rivers while armed and on horseback, without breaking line.

Batavia was already referred to by the Roman leader Julius Caesar as the "Island of the Batavi" (Latin: Insula Batavorum) in his account of his campaigns in Gaul in 58–52 BC — although he did not explain who the Batavi were. Tacitus, writing in about 100 AD, reported that they had a special old alliance (antiquae societatis) with the empire as major contributors to the Roman military, and they did not pay any other form of tribute or tax. Some modern scholars have suggested that this relationship was established by Caesar himself who had a Germanic cavalry unit which fought for him in Gaul, and then in his Roman civil war. According to these proposals, this force evolved into the later bodyguard of Caesar's imperial successors in the Julio-Claudian dynasty, who continued to recruit Batavians for this role.

The Revolt of the Batavi took place in the Roman province of Germania Inferior ("Lower Germania") between AD 69 and 70. It was an uprising against the Roman Empire started by the Batavi, a small but militarily powerful Germanic tribe that inhabited Batavia, on the delta of the river Rhine. They were soon joined by the Celtic tribes from Gallia Belgica and some Germanic tribes.

Under the leadership of their hereditary prince Gaius Julius Civilis, an auxiliary officer in the Imperial Roman army, the Batavi and their allies managed to inflict a series of humiliating defeats on the Roman army, including the destruction of two legions. After these initial successes, a massive Roman army led by the Roman general Quintus Petillius Cerialis eventually defeated the rebels. Following peace talks, the Batavi submitted again to Roman rule, but were forced to accept humiliating terms and a legion stationed permanently on their territory, at Noviomagus (modern day Nijmegen, The Netherlands).