 Theophrastus wrote more logical treatises than Aristotle, though most of them deal with topics similar to those of the Aristotelian treatises. The fragments and later testimonies that have survived from his contributions to logic are mainly to be found in the ancient commentaries of Aristotle’s logical works. Theophrastus is reported there to have improved over some parts of the Aristotelian syllogistic, but he is also supposed to have introduced a number of innovations, sometimes independently sometimes working together with his colleague Eudemus of Rhodes.