Tencteri The Tencteri or Tenchteri or Tenctheri ( in Plutarch ' s Greek , Tenteritē and possibly the same as the Tenkeroi mentioned by Claudius Ptolemy if these were not the Tungri ) were an ancient tribe , who moved into the area on the right bank ( the northern or eastern bank ) of the lower Rhine in the 1st century BC . They are known first from the surviving works of ancient authors such as Julius Caesar and Tacitus . While the Tencteri were referred to by the Romans as Germanic rather than Gauls , their recorded names are most reasonably explained as Celtic : " Tencteri " is generally translated as " the faithful " . Tencteri and Usipetes in the time of Julius Caesar . In his " Commentarii de Bello Gallico " , Caesar describes how two tribes , the Tencteri and Usipetes , had been driven from their traditional lands by the Germanic Suebi , whose military dominance had led to constant warfare and neglect of agriculture . This original homeland of the two tribes is not clear but must have been close to where the Suebi had settled by the time of Caesar , who he described as living in a very large wooded area to the east of the Ubii , who at this time lived on the east bank of the Rhine , on the opposite bank from where Cologne is today . It has been argued that the Tencteri and Usipetes specifically may have come from the area of the Weser river to the east of the Sigambri , because it is near to where the two tribes appeared on the Rhine , and Caesar reports the Suevi in this area . It would also explain the apparently friendly relations of the Tencteri and Usipetes with the Sigambri , who might have been their traditional neighbours . ( In later Roman times this area inhabited by Caesar ' s Suebi was inhabited by the Chatti . ) In the winter 55 BC , having failed to find new lands elsewhere in Germania , they came to the mouth of the Rhine , into the territory of the Menapii , a Belgic tribe which had land on both sides of the river and had not yet submitted to Roman rule . Alarmed by the scale of the incursion , the Menapii had withdrawn from their territories east of the Rhine and successfully resisted the Germani bid to cross it for some time . The Germani feigned a retreat , allowing the Menapii to return to their territories east of the Rhine . Their cavalry then returned and made a surprise night attack . They crossed the river and seized Menapian boats , occupied Menapian villages and towns , and spent the rest of the winter living on Menapian provisions . Caesar , fearing how the Gauls on the left bank might react , hurried to deal with this threat to his command of the region . He discovered that a number of Gaulish tribes had attempted to pay these Germani generously to leave , but the Tencteri and Usipetes had ranged further , coming to the frontiers of the Condrusi and Eburones , who were both under the protection of the Treveri to their south . Caesar convened a meeting of the Gaulish chiefs , and , pretending he did not know of their attempts at bribery , demanded cavalry and provisions for war against the Tencteri and Usipetes . The Tencteri and Usipetes sent ambassadors to Caesar as he advanced . While they boasted of their military strength , claiming that they could defeat anyone but the Suebi , they offered an alliance , requesting that Caesar assign them land . Caesar refused any alliance so long as the Tencteri and Usipetes remained in Gaul . He proposed settling them in the territory of the Ubii , another Germanic tribe who had sought his help against the aggression of the Suebi , there being no land available in Gaul . The ambassadors requested a truce of three days , during which time neither side would advance towards the other , and they took Caesar ' s counter - proposal to their leaders for consideration . But Caesar would not accept this , believing the Germani were buying time for the return of their cavalry , who had crossed the Meuse to plunder the Ambivariti a few days previously . As Caesar continued to advance , further ambassadors requested a three - day truce for them to negotiate with the Ubii about his settlement proposal , but Caesar refused for the same reason . He offered a single day , during which he would advance no more than four miles , and ordered his officers to act defensively and not to provoke battle . The Germanic cavalry , although outnumbered by Caesar ' s Gallic horsemen , made the first attack , forcing the Romans to retreat . Caesar describes a characteristic battle - tactic they used , where a horsemen would leap down to their feet and stab enemy horses in the belly . Accusing them of violating the truce , Caesar refused to accept any more ambassadors , arresting some who came requesting a further truce , and led his full force against the Germanic camp . The Usipetes and Tencteri were thrown into disarray and forced to flee , pursued by Caesar ' s cavalry , to the confluence of the Rhine and Meuse . Many were killed attempting to cross the rivers . They found refuge on the other side of the Rhine amongst the Sicambri . Plutarch reports that back in Rome , Cato pronounced the opinion that they ought to deliver up Caesar to the Barbarians , thus purging away the violation of the truce in behalf of the city , and turning the curse therefor on the guilty man . Of those who had crossed the Rhine into Gaul four hundred thousand were cut to pieces , and the few who succeeded in making their way back were received by the Sugambri , a German nation . This action Caesar made a ground of complaint against the Sugambri , and besides , he coveted the fame of being the first man to cross the Rhine with an army . Later mentions . In 16 BC , the Tencteri , Usipetes and Sicambri once again crossed the Rhine and attacked Gaul . Marcus Lollius was defeated and the Germanic tribes took the standard of the 5th legion . Tacitus describes the Tencteri as living in his time ( approximately 98AD ) , and also at the time of the Batavian revolt ( 69 / 70 AD ) , between the Chatti and the Rhine , across from the Ubii who had been settled in Cologne . This means that they had settled in the area once inhabited by the Ubii ( which is what Caesar had been considering already in his time ) . The Sicambri to the north of this area , had also apparently been moved by this time , and possibly partly replaced by their neighbours the Tencteri and Bructeri . Orosius reports that the Tencteri , and not only the Sicambri and Usipetes , were defeated by Drusus . Later , the difficult to interpret description given in Claudius Ptolemy ' s " Geography " describes the " Tenkeroi " and " Incrionoes " living between the Rhine and the Black Forest ( Abnoba ) mountain range , implying that the Tencteri had moved southwards up the Rhine . In the Peutinger map , the area across from Cologne and Bonn is inhabited by the " Burcturi " ( Bructeri ) , who may have included a mixture of several of the original Germanic tribes from over the Rhine , including the Tencteri and Usipetes . To their north are Franks and their south on the Rhine were Suevi .