As the chronology of antiquity became more refined, increasingly bizarre efforts were made to attach precise dates to episodes embalmed in myths, often by means of some internal evidence as the mention of a datable astronomical event like the appearance of a comet or an eclipse. An alternative to euhemerism is to believe that myths are allegories of goings-on in the universe around us: myths are not history, but natural history. The supposition that pagan myths are to be understood as allegories of natural processes on earth seems to have been entertained as early as the sixth century B.C. by Theagenes of Rhegium. The rediscovery of mythology as an encyclopedia of psychological types and universal emotions stimulated writers to take a new interest in the old myths. Critics of the moralistic approach complained that it made neither good theology nor good sense to scour pagan myths for Christian messages.