1.5
But Medea, being then wedded to Aegeus, plotted against himThat Theseus was sent against the Marathonian bull at the instigation of Medea is affirmed also by the First Vatican Mythographer. See Scriptores rerum mythicarum Latini, ed. Bode, i. p. 18, (First Vatican Mythographer, Fab. 48). Compare Plut. Thes. 14; Paus. 1.27.10; Ov. Met. 7.433ff. As to Medes at Athens, see above, Apollod. 1.9.28. and persuaded Aegeus to beware of him as a traitor. And Aegeus, not knowing his own son, was afraid and sent him against the Marathonian bull.
1.6
And when Theseus had killed it, Aegeus presented to him a poison which he had received the selfsame day from Medea. But just as the draught was about to be administered to him, he gave his father the sword, and on recognizing it Aegeus dashed the cup from his hands.Compare Plut. Thes. 12; Scholiast on Hom. Il. xi.741; Ov. Met. 7.404-424. According to Ovid, the poison by which Medea attempted the life of Theseus was aconite, which she had brought with her from Scythia. The incident seems to have been narrated by Sophocles in his tragedy Aegeus. See The Fragments of Sophocles, ed. A. C. Pearson, vol. i. pp. 15ff. And when Theseus was thus made known to his father and informed of the plot, he expelled Medea.