Gallic Wars
The Gallic Wars were a series of military campaigns waged by the Roman proconsul Julius Caesar against several Gallic tribes. Rome's war against the Gallic tribes lasted from 58 BC to 50 BC and culminated in the decisive Battle of Alesia in 52 BC, in which a complete Roman victory resulted in the expansion of the Roman Republic over the whole of Gaul (mainly present-day France and Belgium). While militarily just as strong as the Romans, the internal division between the Gallic tribes helped ease victory for Caesar, and Vercingetorix's attempt to unite the Gauls against Roman invasion came too late. The wars paved the way for Julius Caesar to become the sole ruler of the Roman Republic.
Wallonia
Julius Caesar conquered Gaul in 57 BC. The Low Countries became part of the larger Gallia Belgica province which originally stretched from southwestern Germany to Normandy and the southern part of the Netherlands. The population of this territory was Celtic with a Germanic influence which was stronger in the north than in the south of the province. Gallia Belgica became progressively romanized. The ancestors of the Walloons became Gallo-Romans and were called the "Walha" by their Germanic neighbours. The "Walha" abandoned their Celtic dialects and started to speak Vulgar Latin.