warfare of both the Gauls and the Britons. The Gallic Wars were a series of military campaigns waged by the Roman proconsul against Gallic tribes, lasting from 58 BC to 51 BC. The Romans would also raid Britannia and Germania, but these expeditions never developed into full-scale invasions. The Gallic Wars 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. These wars paved the way for Caesar to become the sole ruler of the Roman Republic. Descriptions of battles against various Gallic tribes, heavily contrasts the popular picture of the wild and naked Celtic warrior. Caesar even speaks of the Helvetii fighting in close order in an organized fashion, forming a phalanx as a defense against cavalry and advancing in a close formation. He also speaks of arrows being used against his troops crossing rivers and against the besiegers of Gergovia, capital of the Arverni - one of the few engagements in which Vercingetorix outmanoeuvred Caesar. He mentions the use of javelins by the Belgic tribe, the Nervii, but despite Roman writers frequently referring to the use of swords by the Celts in battle, Caesar never mentions Gallic troops fighting en masse with swords. By the mid-1st century BC, Celtic tribes in Gaul may have had a core of properly trained and equipped Gallic leaders, in addition to the tribal levy of lightly armed and armored Gauls. It is perhaps the descriptions of the Britons which have most influenced the popular image of the wild Celtic berserker. Caesar purposefully emphasized the "barbarian" aspect of the Britons for political reasons since his expedition was brief out of necessity, describing how they wore animal skins, had wives in common, did not grow crops and they dyed and tattoo their skin blue: although his description does not mention which plant was used, subsequent commentators have supposed that woad was the source of this blue dye and though later experimentation suggests that woad is not very well suited as a skin dye nor as tattoo ink, this image, when conflated with the descriptions of the Gaesatae, has nevertheless helped paint the picture of the woad-daubed ancient Briton or Pict charging into battle naked and blue. The other popular image of pre-Roman Britain, the scythed chariot, is not mentioned by Caesar either but alluded to