Caesar defeated the "Helvetii" in 58 BC at the Battle of the Arar and Battle of Bibracte, the Belgic confederacy known as the "Belgae" at the Battle of the Axona, the "Nervii" in 57 BC at the Battle of the Sabis, the "Aquitani", "Treviri", "Tencteri", "Aedui" and "Eburones" in unknown battles, and the "Veneti" in 56 BC. In 55 and 54 BC he made two expeditions to Britain. In 52 BC, following the Siege of Avaricum and a string of inconclusive battles, Caesar defeated a union of Gauls led by Vercingetorix at the Battle of Alesia, completing the Roman conquest of Transalpine Gaul. By 50 BC, the entirety of Gaul lay in Roman hands. Caesar recorded his own accounts of these campaigns in "Commentarii de Bello Gallico" ("Commentaries on the Gallic War").