 Cicero, 1st c. BCE: one of our indispensable sources for (the debates among the) schools of Hellenistic philosophy, esp. Stoicism, Epicureanism, and Academic Skepticism: Academics (book two deals with questions of epistemology from Stoic and Academic Skeptic angles); On the Chief Ends of Good and Evil; On the Nature of the Gods (contrasting Epicurean and Stoic views on nature and the gods and criticizing them from the viewpoint of moderate Skepticism); On Fate (hellenistic arguments pro and contra determinism); On Duties (largely based on a treatise of the Middle Stoic Panaetius). (Broad)