Hesiod, Shield of Heracles

Upon the shield Pursuit and Flight were wrought, [155] and Tumult, and Panic, and Slaughter. Strife also, and Uproar were hurrying about, and deadly Fate was there holding one man newly wounded, and another unwounded; and one, who was dead, she was dragging by the feet through the tumult. She had on her shoulders a garment red with the blood of men, [160] and terribly she glared and gnashed her teeth. And there were heads of snakes unspeakably frightful, twelve of them; and they used to frighten the tribes of men on earth made war against the son of Zeus; for they would clash their teeth when Amphitryon's son was fighting: [165] and brightly shone these wonderful works. And it was as though there were spots upon the frightful snakes: and their backs were dark blue and their jaws were black. Also there were upon the shield droves of boars and lions who glared at each other, being furious and eager: [170] the rows of them moved on together, and neither side trembled but both bristled up their manes. For already a great lion lay between them and two boars, one on either side, bereft of life, and their dark blood was dripping down upon the ground; [175] they lay dead with necks outstretched beneath the grim lions. And both sides were roused still more to fight because they were angry, the fierce boars and the bright-eyed lions.