Metamorphoses by Ovid

Priam the sire, much mourn'd, to him unknown That still his son, on pinions borne, surviv'd: While Hector and his brethren round the tomb, A name alone possessing, empty rites Perform'd. Save Paris, from the solemn scene None absent were; he with the ravish'd wife Brought to his shores a long protracted war. Quick was he follow'd by confederate ships Ten hundred, and the whole Pelasgian race. Nor had their vengeance borne so long delay, But adverse raging tempests made the main Impassable; and on Boeotia's shores, In Aulis' port th' impatient vessels bound.

Here, while the Greeks the rites of Jove prepare, Their country's custom, as the altar blaz'd, They saw an azure serpent writhe around A plane, which near the altar rear'd its boughs. Its lofty summit held a nest; within Eight callow birds were lodg'd; on these he seiz'd, And seiz'd the mother, who, with trembling wings, Hover'd around her loss, all burying deep Within his greedy maw. All stare with dread. But Thestor's son, prophetic truths who still Beheld, exclaim'd--"Rejoice! O Greeks, rejoice! "Conquest is ours, and lofty Troy must fall. "But great our toil, and tedious our delay." Then shew'd the birds a nine years' war foretold. The snake, entwining 'mid the virid boughs, Hard stone becomes, but keeps his serpent's form.