Recordkeeping wasn’t a mundane statistical task in the Incan empire—it was an artform. The khipu-in-question dates to around 1500 CE, and originates from an Incan whose diet mainly consisted of greens and tubers. Since wealthier and respected Incan elites ate much meat and maize, the khipu specimen likely belonged to a commoner. The hair’s oxygen and hydrogen levels show that the mystery individual lived at an altitude roughly 8,560 to 9,186 feet above sea level. “In other words, the individual lived in the highlands, relatively far from the Pacific Ocean,” the study’s authors explained.