Nectanebus, so the tale ran, was King of Egypt, and learned in all the magic arts of that mysterious land. When war threatened he would fill a vessel with water and float upon it enchanted ships of clay. Thus could he divine the success or failure of his country’s arms. One day, however, as he was busy in this spell, the old gods appeared to guide the craft he had designed as models of the hostile fleet. Nectanebus gave up all for lost, shaved his head, and in the disguise of a philosopher, fled to Pella in Macedonia, where he lived by practising the arts of an astrologer and prophet. Olympias consulted him to know whether she might hope to give an heir to her husband Philip, then absent from his capital. Nectanebus bade her expect the honour of a visit from Jupiter Ammon himself, and, dressing in the horns and hieratic robe proper to the character he assumed, became, by her whom he seduced, the father of Alexander the Great. The child was born amid thunder and lightning, and was soon committed to the care of Nectanebus who became his tutor: a clear point of connection with Aristotle, who really filled that office. One day tutor and pupil walked on the edge of a cliff, when the philosopher uttered a prophecy to the effect that Alexander was fated to kill his own father. The boy, who fancied that Philip was meant, took the words so ill that he flung his tutor over the rock, and thus instantly fulfilled the prediction. This tale can be traced from its appearance in the Pseudo-Callisthenes through the series of Byzantine chroniclers—Syncellus, Glycas, John Malala, and the author of the _Chronicon Pascale_—to the later romances where it is repeated and amplified. The whole Middle Age believed it. Not till the fourteenth century did a doubt of its truth appear,[270] and that it was current in the west of Europe at the time of which we write appears plainly in the preface to the _Secreta Secretorum_, which has the following significant remark, ‘which Alexander is said to have had two horns.’[271] The real meaning of the legend probably lay in a patriotic desire to vindicate for Egypt, though subdued by Alexander, the honour of having originated the Greek philosophy.[272] The thirteenth century, however, knew nothing of such explanations; cherishing the tale rather on account of the wild mystery which it breathes. No wonder then if the labours of Michael Scot as an exponent of Aristotle gave some force to the popular idea that he dealt in forbidden arts.