The Aedui leaders during the course of the siege had been corrupted with both gold and misinformation by emissaries of Vercingetorix. Caesar had agreed with the Aedui that 10,000 men would protect his line of supplies. Vercingetorix convinced the chief, Convictolitavis, who had been made chief of the tribe by Caesar, to order the same men to join him upon their arrival at the oppidum. They attacked the Romans who were accompanying their supply train, leaving Caesar in an embarrassing position.