Iron Age

During the Iron Age (grosso modo from thousand B.C. up to our present era) the marshes dried out more and more and the population came closer.
The Belgians, who should later be the bravest of all Celts, moved for instance into our plain in the 4th century B.C. One tribe, in particular, the Morins, settled as close as possible to the sea, on the islands rising above the sea at low tide. And when later the Romans wanted to conquer this part, there was a prickly guerrilla war, from which Caesar was slightly shocked. With sorties from their refuges, among which, indeed, Isera Portus, they fended off the invincible legions. Annoyed and probably to spare himself against Rome, Caesar spoke of an untold swamp, from which you did not know exactly which part was land and which water, with tremendous tides and a poor population living on mounds to keep their feet dry.