In chapter 5 I presented an historical model of the genesis of the Batavians in the Dutch river delta. My central hypothesis is that the formation of a Batavian identity group had its roots in the Caesarian frontier organisation: it emerged from a process of integration between a relatively small immigrant group from the east bank of the Middle Rhine and local indigenous groups. Tacitus describes the Batavians as a branch of the Chatti who had split off in order to settle in the Rhine delta. This move can be dated to the period between Caesar's departure from Gaul (51 BC) and the start of Drusus’ Germanic campaigns (12 BC). The objective of the present chapter is to test this historical model against a numismatic data set relating to the Lower Rhine ‘rainbow cups’ of the triquetrum type. The phase in which these coinages circulated widely – and were probably also struck – in the Rhine delta coincides with the historically documented formation of a Batavian polity. It will be argued that most of the coinages in question were Batavian emissions. Finally, I shall discuss the role these coinages may have played in the integration process of different groups into a new Batavian polity.

DISTRIBUTION, CLASSIFICATION AND CHRONOLOGY OF THE LOWER RHINE TRIQUETRUM COINAGES

In the Late Iron Age, the Lower Rhine region north of Bonn belonged to the northern periphery of coinusing communities. At first pre-Roman coin circulation was a marginal phenomenon. Not until the mid-1st century BC did coin usage expand considerably and local coin production develop. Apart from the more recent AVAVCIA coins of the Scheers 217 type, the so-called ‘rainbow cups’ of the triquetrum type were the principal local coin group. These feature on the convex obverse a cup-shaped profile with a triquetrum inside a ‘laurel wreath’, and on the concave reverse a ‘pyramid’ of point circles and double circles surrounded by a zigzag line. The triquetrum coins were minted in various metals: gold/electrum (rare in the Lower Rhine region), silver, and a copper alloy. Their weight fluctuates between 7.5 and 4.5 grams. The history of this coin group, which spans almost the entire 1st century BC, began in the area east of the Middle Rhine.