The task seemed beyond his reach, till Medea, the wicked witch, daughter of Æetes, promised to help him, on condition that he would marry her, and take her to Greece.  When Jason had sworn to do so, Medea gave him an ointment with which to rub himself, also his shield and spear.  For a whole day afterwards neither sword nor fire should hurt him, and he would thus be able to master the bulls.  So he found it; he made them draw the plough, and then he sowed the teeth, which came up, like those sown by Cadmus, as armed men, who began to attack him; but, as Medea had bidden him, he threw a stone among them, and they began to fight with one another, so that he could easily kill the few who spared each other.