Cerethrius was a GallicThe Oxford Illustrated History of Prehistoric Europe (Oxford Illustrated Histories) by Barry Cunliffe,2001,page 380 king in

Thrace Thrace (, ; ; ; ) is a geographical and historical region in Southeast Europe roughly corresponding to the province of Thrace in the Roman Empire. Bounded by the Balkan Mountains to the north, the Aegean Sea to the south, and the Black Se ...

. He was defeated in 277 BC, by Antigonus II Gonatas at the Battle of Lysimachia.

References

Celtic warriors Ancient Thrace 3rd-century BC Gaulish tribal chiefs {{Ancient-Thrace-stub