In the adyton at the temple of Apollo, the Pythia, mouthpiece of the oracle, sat on a tripod and awaited the next inquisitor.

From the chasm beneath her, where ancient fault lines crossed, rose the pneuma: the breath of Apollo. Inhaling the vapour, the Pythia began to sway as she descended into the first trance of the day. Although the gas had the sweet odour of perfume, frequent and prolonged inhalation inevitably led first to headaches, then seizures, and finally, to the appointment of the next candidate from the ranks of eager hopefuls.

Still, there was little point in complaining. Unlike the attendant priests and priestesses at the temple, the Pythia did not achieve her position as a result of noble birth or family connections. At the age of 16 and on the verge of starvation, she had been chosen by the Delphic sisterhood to undergo months of rigorous and often painful mental and physical conditioning.

Perhaps today Apollo would be a little kinder to the Pythia…

On the winding path leading up to the temple, Pausinias stopped for a moment to catch his breath. The early morning Sun was hot and the air heavy for this time of year. A traveller from afar, Pausinias had learned of the oracle from an essay by Plutarch, who had been a priest at the temple a generation before. Even in that time, Plutarch despaired that the oracle's well of prophecy was drying up. Apollo's mouthpiece had become more interested in cows, pigs and the ailments of private citizens than in affairs of state.

Pausinias despaired also, in his own way. At 50, he had yet to make a lasting mark on the world, despite travelling across much of it and having learned much.

Unlike others, Pausinias scorned the practice of pawing through animal entrails in search of mystical answers to very mundane questions. Only the ignorant wasted their lives and earnings searching for portents in the guts of animals, the tumble of bones, even the sky above; Pausinias knew better. He had studied the motion of the planetary spheres as set down by Plato and Eudoxus, and understood the mathematical treatise of Pythagoras.

From the work of Erastothenes, Pausinias knew that the circumference of the Earth was some 250,000 stadia, and Hipparchus had demonstrated conclusively that the distance to the Moon was between 59 and 65 times the radius of the Earth. Furthermore, from the writings of Aristarchus, Pausinias accepted that the Sun was some 19 times further from the Earth than was the Moon, and that the points of light seen in the sky at night were not merely dots painted on the spheres, but other, far more distant suns.

The unpopular Aristarchus, rather than believing that these heavenly objects revolved around the Earth, held that the Earth turned on its axis every 24 hours, and, along with the outer spheres, revolved around the Sun. Thus, the movements of the heavens were subject to celestial mechanics, and thence cared not for the whims of the seers or the feeble hopes of their gullible followers (such thoughts secretly pleased Pausinias).

And so Pausinias believed that there was nothing under the Sun that could not eventually be understood by man if only he took the time to make careful observations that could be tested against a given explanation. Reason alone separated man from animals and women. Armed with his knowledge of astronomy, Pausinias would put the Pythia to the test and ask for the date of the next eclipse of the Moon.

If the Pythia answered correctly, then Pausinias would be the first to use mathematics to confirm the veracity of the oracle (after all, a woman could not understand the motions of the spheres). On the other hand, if - as Pausinias privately believed - Apollo's breath reeked of chicken guts, then he still would be remembered by history, however brief his sojourn at Delphi. All in all, given that he could not lose, Pausinias considered that his tiring journey would be a most worthwhile endeavour…