The Caerosi (or Caeroesi) were a small Belgic-Germanic tribe that lived in Gallia Belgica during the Iron Age and the Roman period. Their ethnic identity remains uncertain. Caesar described them as part of the Germani Cisrhenani, but their tribal name is probably of Celtic origin.[1][2][3] Like other Germani Cisrhenani tribes, it is possible that their old Germanic endonym came to be abandoned after a tribal reorganization, that they received their names from their Celtic neighbours, or else that they were fully or partially assimilated into Celtic culture at the time of the Roman invasion of the region in 57 BC.[2]