The Greeks first tried to settle in Celtic Gaul and managed to establish a small colony in Marseille in 600 BC. Then it was the turn of the Romans, lead by Julius Caesar, who entirely invaded Gaul during the Gallic Wars (58-51 BC). The Romans brought unity and peace for two centuries of Pax Romana during which agriculture, cattle-breeding and urban development were greatly improved.
During the 2nd century AC, Romans brought Christianity into Gaul and by the third century, the power of the Roman Empire had begun its decline. The 4th century started with Barbarian invaders from the East such as the Franks, the Vandals and the Visigoths. Clovis, King of the Franks, converted to christianity and his power brought unity to Gaul, starting the Merovingian dynasty.