Theobromine, whose name means "food of the gods," is a bitter alkaloid -- a chemical cousin to caffeine and, like caffeine, a stimulant.

Unlike caffeine, theobromine only occurs naturally in one plant: cacao. Chocolate lovers know that this is the plant to which we owe our favorite treat.

Now theobromine has given scientists a clue to how many centuries humans have been enjoying the fruit of the cacao tree -- and it's about five hundred years longer than we used to think.

According to reports from BBC News, Reuters, and other news sources, archaeologists found pottery vessels about three thousand years old in Puerto Escondido, Honduras. These long-necked bottles contained residue of theobromine.

Later Mesoamerican peoples such as the Maya and the Aztec enjoyed beverages made from ground cacao beans, water, and added flavorings such as spices and certain flower blossoms. However, the new (or rather old) pottery seems to have been used for a beverage made not from the beans, but from the sweet pulp that encases them inside the cacao pods.

The drink didn't taste anything like cocoa as we know it, or even as the Aztecs knew it. Their brew was cold, harsh, and usually unsweetened, but must have had the distinctive "bite" modern dark chocolate enthusiasts are well acquainted with. The pulp of the cacao pod, however, is sweet and has no chocolate taste.

It's hard to exaggerate how different in character and flavor drinks prepared from the pulp and the bean of the cacao would be. Yes, they both come from the pod of the cacao; but the fruit and the peel of a banana are from the same fruit of the same plant, and are remarkably separate in taste and texture. Anyone who has eaten both the roasted seed and the pureed rind of a pumpkin can attest that one fruit can produce two vividly different eating experiences.

Another difference between later cacao beverages and the earlier sweet one is that the latter was probably fermented. Professor John Henderson of Cornell University was quoted by the BBC News as stating that this brew might have contained "up to 5% alcohol in volume."

Apparently it was consumed on special occasions such as weddings and births, to demonstrate the high status of the family. Not much different from how, at weddings, christenings, and naming ceremonies, we often serve sweet, mildly alcoholic beverages.

How appropriate, to those of us who adore chocolate in all its myriad forms, to think that three thousand years ago, a cacao beverage was the champagne of the time and place.