The chocolate tree’s scientific name, Theobroma cacao, comes from theobroma, or ''food of the gods’’ in Greek and cacao from the Olmec word kakawa. The Olmec were the prehistoric inhabitants of Mexico and probably the first consumers of chocolate. The oldest trace of cacao found was in an Olmec jug dating to 600BC, excavated near Colha in Belize. The Mayans who followed them called the drink cacahuatl (''atl’’ means water). They liked their chocolate hot and frothy, flavoured with chilli and vanilla, sculpting tubes into their pots so they could blow the liquid into a foam. The Aztecs also went for foam, but preferred theirs served cold. They also used the beans as currency: a rabbit was worth 10 beans; a slave, 100 beans. The standard weight measure was a carga, which was the total weight of cocoa beans a healthy person could carry (24,000 on a good day). Chocolate was the ultimate man’s drink, drunk by warriors to stimulate aggression and sexual performance and sacrificial victims just before they had their chests cut open and their still-beating hearts pulled out. Conquered peoples had to pay the Aztecs tribute in beans.