Of all Greek heroes, Theseus, few would deny, has the greatest claim to enshrine all the best qualities of the Athenian citizen, not least in his championship of the demos, celebrated by poets and painters alike of the classical period. It might seem at first sight contradictory to find in the same period in Athenian history an equally flourishing tradition concerning Theseus the heroic-age king. This ‘contradiction', however, as it might be perceived in abstract terms by a modern constitutional historian, would not have been felt so acutely, if at all, by a fifth-century Greek, for whom the ideas of monarchic rule and the heroic age were fundamentally connected. Our response to this type of problem owes more to the analytical method of such later works as Aristotle's Politics, with its thorough categorization of constitutions, and there is always the danger that we may impose on the Greek mythological imagination of the fifth century an unwarranted rigidity that fails to reflect the greater plasticity of the classical Greek mind. A review of the Theseus legend in fifth-century Athens reveals the extent to which such flexibility of attitude existed and throws some light on the classical attitude to one-man rule.