The Helvetii were a Celtic tribe that inhabited the region of modern-day Switzerland during the late Iron Age. They are best known for their migration in 58 BCE, when they attempted to move to Gaul in search of better land. This journey was significant in the context of Julius Caesar's campaigns, as it led to the famous conflict known as the Battle of Bibracte. The Helvetii's migration was prompted by population pressures and the desire for fertile territory. Their journey was marked by encounters with other tribes and ultimately led to their defeat by Caesar's forces. This event played a crucial role in the expansion of Roman influence in Western Europe.