When Rhea gave birth to Zeus, she put him in a cave, located at Mount Ida in the island of Crete. In this way, his father Cronus would be unable to find him and swallow him, which he had done with his previous children. There, it was the goat Amalthea (Amaltheia) that nourished Zeus with her milk until he was grown up.
One day, as young Zeus played with Amalthea, he accidentally broke off her horn. To make up for it and as a sign of gratitude, Zeus blessed the broken horn, so that its owner would find everything they desired in it. It became known as the Horn of Amalthea or the Cornucopia, an eternal symbol of abundance. When Amalthea died, Zeus used her hide to create his thunder-shield (the Aegis).