Viriathus was the most important leader of the Lusitanian people who resisted the Roman expansion into western Hispania. As a shepherd who became a hunter and soldier, Viriathus led the Lusitanians for many years until 139 BC, when he was betrayed by Lusitanian ambassadors and killed, allowing the Romans to further advance across the Iberian Peninsula. Viriathus is considered the first hero of Portugal for his defense of the Lusitanian people against Roman conquest.