Our understanding of Machu Picchu's timeline wasn't quite right, or so a new study published in Antiquity suggests. It's long been thought that the Peruvian site was built after AD 1438, reports the Guardian, a conclusion that was drawn from the accounts of Spanish conquistadors who were present in the 1500s. Advanced radiocarbon dating techniques—specifically accelerator mass spectrometry dating of the remains of 26 people who were excavated in 1912—indicated the site was first used in 1420 at the latest. "This is the first study based on scientific evidence to provide an estimate for the founding of Machu Picchu and the length of its occupation," says study author Richard Burger of Yale. As far as length goes, Burger and his colleagues found "a single unbroken occupation ... between c. AD 1420 and 1530," which syncs with when the Spaniards began their rout of the Inca empire.
- This matters because: It "[raises] questions about our understanding of Inca chronology," as YaleNews puts it. The accepted timeline, based on those accounts from Spanish invaders, had Inca Emperor Pachacuti come to power in 1438 and then seize control of the lower Urubamba Valley where Machu Picchu was constructed beginning around 1440. The results suggest Pachacuti's initial conquests occurred earlier than thought.
- The study authors' take: "Given the unreliability of the documentary evidence, perhaps the time has come for the radiocarbon evidence to assume priority in reconstructions of the chronology of the Inca emperors and the dating of Inca monumental sites such as Machu Picchu."
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