 Religions are not free-floating products of reason. They are based on tradition and the establishment of authority. Tradition of course is itself a product of evolution over time. But once something can be talked of as a religion, it already has in place structures and a history that can be seen to be reasonably deep-rooted and which, although it can evolve, must retain a sense of connection with those roots. In the religious context, tradition rather than reason is the principal authority, whether that be located in founding figures or documents, in time-honoured ceremonies and rituals, or in leaders who can claim to inherit the mantle of authority via their own devotion to the tradition – in the Roman context, the high priests whom Cotta affirms that he defers to on religious matters, rather than Stoic theorists (3.5).