The siege of Alesia was a decisive battle of the Gallic Wars. It resulted in the defeat of a coalition of Gallic tribes led by Vercingétorix against the Roman army of Julius Caesar in 52 BC. To increase his own prestige and expand the territory of the Roman Republic, Julius Caesar intervened in Gallic affairs as early as 58 BC and quickly controlled much of Gaul. In 52 BC, to organize the Gallic revolt, the Arverne chief Vercingétorix gathered numerous people from the center of Gaul. In the spring, he managed to repel the Roman assaults at the siege of Gergovie in the Puy-de-Dôme department but was surrounded in the oppidum of Alesia (reconstituted here) in the Côte-d'Or department during the summer.