Portents and prodigies
For the ancient Greeks, portents and prodigies had a tangible and enduring impact on their attitudes towards activities they were planning or undertaking. Portents were important enough in the practice of divination to encourage an author to describe and interpret them: Pausanias notes that Hesiod wrote a work concerned with the interpretation (exegesis) of portents (terata). Popular meteorology – what the ordinary Greek thought of as omens from heaven – was very different from the 'scientific' meteorology which the sixth- and fifth-century natural philosophers and thinkers had developed in seeking a rational explanation for 'inexplicable' happenings that took place on earth and in the solar system. Terata were events and happenings within specific contexts that forewarned of what was to come. In military contexts, commanders had to be aware of the necessity for counteracting ill-omened terata which were the result of natural causes.