Gallic Wars (58 BC-51 BC). Siege of Alesia, 52 BC. The climactic military confrontation of the Gallic Wars, fought around the Gallic oppidum (fortified settlement) of Alesia in present-day France, an important centre of the Mandubii tribe. Julius Caesar's Roman army fought against a confederation of united Gaulish tribes under the leadership of Vercingetorix of the Arverni. It was the last major battle between Gauls and Romans, and is considered one of Caesar's greatest military achievements. The Roman army built two lines of fortifications: an inner wall to keep the besieged Gauls in and an outer wall to keep the Gallic relief force out. The Battle of Alesia marked the end of Gallic independence in what is now France and Belgium. Strong attack on the Roman trenches by the Gauls, who were repulsed. Engraving. Detail. "Commentaires de Cesar, avec des notes historiques, critiques et militaires, by Count Turpin de Crisse". Volume II. Paris, 1785.