The Gallic Wars were waged between 58 BCE and 50 BCE by the Roman general Julius Caesar against the peoples of Gaul (present-day France, Belgium, along with parts of Germany and the United Kingdom). Gallic, Germanic, and British tribes fought to defend their homelands against an aggressive Roman campaign. The Wars culminated in the decisive Battle of Alesia in 52 BCE, in which a complete Roman victory resulted in the expansion of the Roman Republic over the whole of Gaul. Though the Gallic military was as strong as the Romans, the Gallic tribes' internal divisions eased victory for Caesar. Gallic chieftain Vercingetorix's attempt to unite the Gauls under a single banner came too late. Caesar portrayed the invasion as being a preemptive and defensive action, but historians agree that he fought the Wars primarily to boost his political career and to pay off his debts. Still, Gaul was of significant military importance to the Romans. Native tribes in the region, both Gallic and Germanic, had attacked Rome several times. Conquering Gaul allowed Rome to secure the natural border of the river Rhine. The Wars began with conflict over the migration of the Helvetii in 58 BCE, which drew in neighboring tribes and the Germanic Suebi.