Their exact location is still unknown, although two proposals are, first, that it might be the source of the name of the Belgian village of Geetbets, and second, that it might be further east, nearer to the Sunuci with whom they interacted in the Batavian revolt, and to the Cugerni who lived at Xanten.
[3] As with many of the tribal groups of Germania Inferior, such as the Toxandrians, and Tungrii, the origins of the tribe are unknown, but it is likely that their ancestry included a mixture of older populations and Germanic immigrants from the east of the Rhine who had been arriving for generations.
Caesar and Tacitus were more interested in the fact that tribes from the east of the Rhine, who all eventually came to be referred to as Germani, were less softened by civilization, and therefore difficult to defeat in battle or incorporate into the Roman empire.
Some specific tribes who entered the empire later, such as the Ubii who lived on the west bank of the Rhine, are understood to be speakers of Germanic languages, and records exist concerning their immigration and settlement.
It has been proposed that like their neighbours the Cugerni, they descend from the Sicambri, who were already actively jumping to this side of the Rhine in Caesar's time, and who Strabo records as living in this area.
[1] On the other hand there have been suggestions that they might represent the descendants, at least partly, of the Germani tribes described by Caesar as having been in this region since at least the 2nd century BCE when the Cimbri moved through the area.