Commius Commius ( Commios , Comius , Comnios ) was a historical king of the Belgic nation of the Atrebates , initially in Gaul , then in Britain , in the 1st century BC . Ally of Caesar . When Julius Caesar conquered the Atrebates in Gaul in 57 BC , as recounted in his " Commentarii de Bello Gallico " , he appointed Commius as king of the tribe . Before Caesar ' s first expedition to Britain in 55 BC , Commius was sent as Caesar ' s envoy to persuade the Britons not to resist him , as Caesar believed he would have influence on the island . However he was arrested as soon as he arrived . When the Britons failed to prevent Caesar from landing , Commius was handed over as part of the negotiations . Commius was able to provide a small detachment of cavalry from his tribe to help Caesar defeat further British attacks . During Caesar ' s second expedition to Britain Commius negotiated the surrender of the British leader Cassivellaunus . He remained Caesar ' s loyal client through the Gaulish revolts of 54 BC , and in return Caesar allowed the Atrebates to remain independent and exempt from tax , and in addition appointed Commius to rule the Morini . However this loyalty was not to last , as related by Aulus Hirtius in the final book of the " De Bello Gallico " , written after Caesar ' s death . While Caesar was in Cisalpine Gaul in the winter of 53 , the legate Titus Labienus believed that Commius had been conspiring against the Romans with other Gaulish tribes . Labienus sent a tribune , Gaius Volusenus Quadratus , and some centurion s to summon Commius to a sham meeting at which they would execute him for his treachery , but Commius escaped with a severe head wound . He vowed never again to associate with Romans . Enemy of Caesar . In 52 BC the Atrebates joined the pan - Gaulish revolt led by Vercingetorix , and Commius was one of the leaders of the army that attempted to relieve Vercingetorix at the Siege of Alesia . After Vercingetorix was defeated Commius joined a revolt by the Bellovaci and persuaded some 500 Germans to support them , but this too was defeated and Commius sought refuge with his German allies . In 51 BC he returned to his homeland with a small mounted war - band for a campaign of agitation and guerrilla warfare . That winter Mark Antony , a legionary legate at the time , ordered Volusenus to pursue him with cavalry , something Volusenus was more than happy to do . When the two groups of horsemen met Volusenus was victorious , but sustained a spear - wound to the thigh . Commius escaped and sued for peace through intermediaries . He offered hostages and promised he would live where he was told and no longer resist Caesar , on the condition that he never again had to meet a Roman . Antony granted his petition . A 1st century AD source , Sextus Julius Frontinus ' s " Strategemata " , tells how Commius fled to Britain with a group of followers with Caesar in pursuit . When he reached the English Channel the wind was in his favour but the tide was out , leaving the ships stranded on the flats . Commius ordered the sails raised anyway . Caesar , following from a distance , assumed they were afloat and called off the pursuit . This suggests that the truce negotiated with Antony broke down and hostilities resumed between Commius and Caesar . However John Creighton suggests that Commius was sent to Britain as a condition of his truce with Antony - where better to ensure that he never again met a Roman ? - and that Frontinus ' s anecdote either refers to an escape prior to the truce , or is historically unreliable , perhaps a legend Frontinus heard while governor of Britain ( 75 to 78 AD ) . Creighton argues that Commius was in fact set up as a friendly king in Britain by Caesar , and his reputation was rehabilitated by blaming his betrayal on Labienus ( who deserted Caesar for Pompey in the civil war of 49 - 45 BC ) . Commius ' s name appears on coins of post - conquest date in Gaul , paired with either Garmanos or Carsicios . This suggests he continued to have some power in Gaul in his absence , perhaps ruling through regents . Alternatively , Garmanos and Carsicios may have been Commius ' s sons who noted their father ' s name on their own coins . King in Britain . By about 30 BC Commius had established himself as king of the Atrebates in Britain , and was issuing coins from Calleva Atrebatum ( Silchester ) . It is possible that Commius and his followers founded this kingdom , although the fact that , when Caesar was unable to bring his cavalry to Britain in 55 BC , Commius was able to provide a small detachment of horsemen from his people , suggests that there were already Atrebates in Britain at this time . Coins marked with his name continued to be issued until about 20 BC , and some have suggested , based on the length of his " floruit " , that there may have been two kings , father and son , of the same name . However , if Commius was a young man when appointed by Caesar he could very well have lived until 20 BC . Some coins of this period are stamped " COM COMMIOS " , which , if interpreted as " Commius son of Commius " , would seem to support the two kings theory . Three later kings , Tincomarus , Eppillus and Verica , are named on their coins as sons of Commius . From about 25 BC Commius appears to have ruled in collaboration with Tincomarus . After his death Tincomarus appears to have ruled the northern part of the kingdom from Calleva , while Eppillus ruled the southern part from Noviomagus ( Chichester ) . Eppillus became sole ruler ca . AD 7 . Verica succeeded him about 15 , and ruled until shortly before the Roman conquest of 43 . Popular culture and fiction . French Nobel laureate Anatole France wrote a lengthy short story about the Romanization of Belgic Gaul from the point of view of Commius , whose name he recasts in Germanic form as Komm . The story , " Komm of the Atrebates , " appears in France ' s historical fiction collection " Clio " and can be read in English translation online . Commius appeared in the 2001 French movie " Vercingétorix . "