In 152 BC the Lusitanians made a peace agreement with Marcus Atilius, after he conquered "Oxthracae", Lusitania's biggest city. In Roman law, peregrini dediticii was the designation given to peoples who had surrendered themselves after taking up arms against the Romans. The terms offered were such that, as soon as Atilius returned to Rome, they rebelled and broke the treaty. Then they attacked the tribes that were Roman subjects and that had sided with the Romans in helping to attack and plunder the Lusitanian towns. Possibly the Lusitanians recovered some of the booty the Romans had divided with those tribes.