 Two other ancient traditions which may have contributed to the development of medieval theories of consequence are the Stoic tradition (see the entry on ancient logic of this encyclopedia, section 5) and the tradition of the ancient commentators (Barnes 1990, 2008; entry on the ancient commentators of this encyclopedia). But in fact, while a Stoic connection is prima facie plausible — unlike Aristotelian term-based logic, Stoic logic is also largely sentence-based — historical evidence for direct Stoic influence remains elusive; for now, no record of actual channels of influence has been  identified.[4]  The ancient commentators, by contrast, had significant (both indirect and direct) impact on the development of the notion of consequence — at first via Boethius, later via the Arabic authors, and as their commentaries were translated and read by the Latin authors in the 13th century and onwards.