In chapter 5 I argued on the basis of historical sources that the Batavian ethnogenesis was closely bound up with Caesarian frontier politics, and I proposed the following historical reconstruction. At the time of the Gallic and subsequent Civil Wars, a treaty existed between Caesar and the leader of a Chatti-dominated group of east-bank Germans, who – probably in the 40s BC - were allocated land in the Rhine/ Meuse delta. The new Batavian polity arose when the dominant core of migrants from across the Rhine merged with indigenous groups. From the outset, then, the Batavian community's existence was closely tied to an alliance with Rome. At the heart of this alliance lay the supply of auxiliary troops, including a cavalry detachment that operated as personal bodyguard to Caesar and the later Julian emperors. In return, the Batavians were exempt from paying tribute and were granted the right to command their own troops. Their leader was probably formally recognised as king by Caesar, rewarded with Roman citizenship and thus incorporated in the clientela of the Julian house. Under Emperor Augustus, the old treaty with the Batavians was transformed into a public alliance with the Roman state.470 Although the kingship was abolished, the Batavian stirps regia retained its dominant political position. Until the death of Nero, the last of the Julio-Claudian line, there had been a solid alliance between Batavians and the emperor, which essentially built on the original treaty provisions.

Links with Rome from the Augustan period onward will have given rise to new types of self-representation among the Batavian community, and their elite in particular. In the Gallic provinces from that time we witness the adoption of new media like public writing and statuary to emphasise the links with the emperor and the imperial house. These new cultural forms also gave voice to local identities in the new context of the Roman empire. I am thinking in particular of the appearance among the Batavians of public monuments that symbolised the allegiance with Rome and the close ties with the Julio-Claudian house. An analogy with the Lingones in Gaul is instructive here. Julius Sabinus, a representative of an aristocratic family that was granted Roman citizenship early on, claimed direct descent from the deified Caesar, who allegedly had had a love affair with his great grandmother during Caesar's stay in Gaul.