Marseille was born on the shores of the once marshy Calanque de Lacydon - today occupied by the Vieux-Port - which has become an ideal port protecting the city from the sea and enemies. The Greeks, traders from Ionia, created the colony of Massalia there and married native women. By adopting the more advanced Greek culture, Massalia became something of a city-state, a small Greece south of barbarian Gaul. It had to protect itself from the invasions of the neighboring Celto-Ligurian tribes under the threat of which it lived. Until 1423, the entrance to the Vieux-Port was blocked by a heavy chain after dark.