46. Seeing, therefore, that men who agree not amongst themselves have all alike conspired against the Church of God, I shall call those whom I have to answer by the common name of heretics. For heresy, like some hydra of fable, hath waxed great from its wounds, and, being ofttimes lopped short, hath grown afresh, being appointed to find meet destruction in flames of fire. Hercules found it impossible to slay the Hydra (a monster water snake) of the Lernean marshes by merely striking off its head, inasmuch as whenever one was cut off, two immediately grew in its place. He was compelled to sear the wound with fire. One of the heads was immortal, and Hercules could only dispose of it by crushing it under a huge rock. Or, like some dread and monstrous Scylla, divided into many shapes of unbelief, she displays, as a mask to her guile, the pretence of being a Christian sect, but those wretched men whom she finds tossed to and fro in the waves of her unhallowed strait, amid the wreckage of their faith, she, girt with beastly monsters, rends with the cruel fang of her blasphemous doctrine. For Scylla and Charybdis, see Homer, Odyss. XI.; Virgil, Æn. III. 424 f. The strait, bestrewed with wreckage of the faith (1 Tim. i. 19) corresponds to the strait between the rock of Scylla and the whirlpool Charybdis. In order to avoid the latter, mariners were compelled to pass close under the former, whereupon the monster darted out and seized them, dragging them out of a ship as an angler whips a fish out of water (Odyss. XI. 251–255). The language of this passage shows plainly that St. Ambrose, in writing it, drew freely upon Virgil.