An alternate theory is that by the 4th century BC, the western Greeks, especially the Massaliotes, were on amicable terms with Carthage. In 348 BC, Carthage and Rome came to terms over the Sicilian Wars with a treaty defining their mutual interests. Rome could use Sicilian markets, Carthage could buy and sell goods at Rome, and slaves taken by Carthage from allies of Rome were to be set free. Rome was to stay out of the western Mediterranean, but these terms did not apply to Massalia, which had its own treaty. During the second half of the 4th century BC, the time of Pytheas' voyage, Massaliotes were presumably free to operate as they pleased; there is, at least, no evidence of conflict with Carthage in any of the sources that mention the voyage.