The Iliad by Homer Book 20 Page 18

It went through two layers, but the god had made the shield in five, two of bronze, the two innermost ones of tin, and one of gold; it was in this that the spear was stayed.

Achilles in his turn threw, and struck the round shield of Aeneas at the very edge, where the bronze was thinnest; the spear of Pelian ash went clean through, and the shield rang under the blow; Aeneas was afraid, and crouched backwards, holding the shield away from him; the spear, however, flew over his back, and stuck quivering in the ground, after having gone through both circles of the sheltering shield. Aeneas though he had avoided the spear, stood still, blinded with fear and grief because the weapon had gone so near him; then Achilles sprang furiously upon him, with a cry as of death and with his keen blade drawn, and Aeneas seized a great