Before chocolate was a pleasure, it was a payment. For the Maya and the Aztecs, the cacao bean was not a treat but a coin; small, portable, countable, and accepted more or less everywhere. You could buy your dinner with it, settle your taxes with it, and pay your workers with it. It was, in every practical sense, money that happened to be delicious.
The going rates
The exchange rates, noted down by faintly scandalised Spanish observers, have a wonderful precision to them. A single bean bought you five green chillies, or twenty small tomatoes. Three beans got you a freshly picked avocado. Thirty beans, a small rabbit. A day's labour might be settled with a hundred. You could, in the most literal sense imaginable, eat your wages, though doing so would have been rather like lighting a cigar with a banknote.
Where there is money, there is forgery
And because a cacao bean was worth something, people faked it. Counterfeiters hollowed out the shells and repacked them with mud, sand, or a bit of avocado pit, then slipped the fakes back into circulation; a warm little husk of nothing, pretending to be wealth. It was patient, fiddly, unglamorous fraud, and it was everywhere. Cacao was, quite plausibly, the most counterfeited currency in the Americas: the first money that could be both eaten and swindled.
When the Spanish arrived in 1519, they found the whole arrangement faintly ridiculous. An entire civilisation running its economy on confectionery. The amusement did not last. They soon grasped the useful half of the idea: that you could pay a labourer in cacao and keep the silver for yourself. The joke, as jokes about money tend to, quietly turned practical.
We think about this more often than is strictly necessary. There is something clarifying about an age when a bean had to be worth its weight, when watering down chocolate was not a marketing decision but a criminal one. We are, in our small way, sympathetic to the sentiment. A cacao bean should contain cacao. Anything else is, historically speaking, fraud.