The Atrebates were a tribe of British Celts living in the area of modern Sussex, Berkshire, and Hampshire. During the 1st and 2nd centuries BCE they were among the most powerful of British tribes, maintaining strong links with related tribes in Gaul.
When Julius Caesar planned his invasion of Britain in 55BCE he used Commius, an Atrebatic chief from Gaul, as a go-between with his British counterparts. Commius then switched sides, supporting Vercingetorix in his revolt against Rome, but when that rebellion failed, he fled to Britain, where he became king of the Atrebates based in Calleva (modern Silchester).
Verica, a descendant (perhaps third son) of Commius, eventually battled and lost the northern half of his kingdom, including the capital of Silchester, to the Trinovantes tribe. Verica may be the "Berikos" who appealed to Rome for help regaining his kingdom, thus providing the excuse for the Emperor Claudius to invade Britain.
After the Claudian invasion of Britain in 43CE the Atrebates were ruled as a client-kingdom of Rome under Cogidubnus (Tiberius Claudius Cogidubnus). There is some speculation that Cogidubnus may even have been raised in Rome.
Later the Atrebatic kingdom was split into three parts, with the capital of the Atrebates at Silchester, the Belgae at Winchester, and the Regini at Chichester.
The known and speculative kings of the Atrebates are as follows:
Commius 45 - 30 BCE
Tincomaros (Tincommius) 30 - 25 BCE
Eppilus 10 BCE - 10 CE
Verica 10 - 43 CE
Epaticcus 35 - 43 CE
Caratacus (Caradog) 43 - 51 CE
Cogidubnus 43 CE >