Inca bureaucrats recorded all the goings-on in their bustling empire using knotted cords called khipu, where the position and order of the knots represented numbers. They relied on the khipu system to track people, taxes, produce, livestock, and products like woven cloth and beer.
Because khipu were so vital to the Inca government, and because the khipu itself is such a sophisticated way of recording numbers, colonial writers decided that these tools must be the exclusive knowledge of a very specialized, elite class of bureaucrats. But a recent study, analyzing hair from a khipu made around 1498 CE, suggests that even common folk had a good grasp of this intricate way of recording numbers.
A lasting signature on a gorgeous piece of work
University of St. Andrews archaeologist Sabine Hyland and her colleagues recently analyzed a stand of hair from a 500-year-old khipu—one they expected to be the handiwork of an especially high-ranking member of the Inca empire, based on how beautifully it was crafted.
“It’s very fine and has subtle embellishments, like decorative braiding on the ends of some pendants. I wondered if this was from a very high-status person indeed,” Hyland told Ars. “It was [a] surprise when we got the results back, and it showed that this person had the diet of a commoner.”
The threads that made up the khipu’s knotted strands had come from a camelid (probably an alpaca or llama), but those strands hung from a cord of human hair: a 104-centimeter-long set of locks, folded in half and twisted into a sturdy cord. Almost certainly, the person who made the khipu intended their hair to serve as a deeply personal signature for their work. For the Inca, hair contained a person’s spiritual essence; it also happens to contain a chemical record that can shed light on what they ate and where they lived.