The cacao came from Quetzalcoatl. He was a god, the god of light. Quetzalcoatl came in all these different forms. There was a legend that cacao came to the people because it was considered food of the gods. Quetzalcoatl was the god of light and he decided, he was looking down at the people and he saw the Toltecan people. They were agronomists but they were having a lot of trouble with their crops and in a very bad position. So he decided to go down, that he was going to go down in human form and take them the cacao. He goes down, takes them in, shows them the seeds, and they plant these cacao seeds, and grow these trees and right off the trunks themselves grow these beautiful pods.
When the time comes and its a full moon they go and harvest the cacao. They take this obsidian spear and chop down the cacao. They open it up and everybody is amazed. There is this pod and inside is all this gooey stuff with seeds inside. Its very aromatic and kind of exotic. Everybody is sucking on these beans and taking part of eating this goo around these seeds. He takes the women and shows them what to do with the seeds. First they dry them in the sun, and then they toast them on the comal, and you wait until you hear that sound, remember that snapping, and that’s when the seeds are ready. He showed them to peel the seeds and then to go to the matate and kneel at the matate and to grind the nibs and make polvo like this color, and then to make a paste.
They make the paste until they can actually see their face. When they see their reflection in the paste, that’s how they know the paste is ready. Its that shiny because all the oil comes out of the cacao.
-Chef Susanna Trilling, from the video, Making Oaxacan Chocolate
3rdarm.biz 
It all began under a full moon.