CUSCO, PERU—A new study of human remains recovered from Machu Picchu in 1912 suggests that the Inca citadel was built two decades earlier than previously thought, CNN reports. On the basis of historical records written by Spanish conquistadors, scholars had believed that the emperor Pachacuti constructed the stone structures as an estate sometime after he rose to power in A.D. 1438. A team led by Yale University archaeologist Richard Burger dated the remains of 26 individuals buried at the site's three cemeteries using accelerator mass spectrometry, an advanced type of radiocarbon dating that allowed the researchers to date skeletons with only small amounts of remaining organic material. Their results show that Machu Picchu was in use as early as A.D. 1420 and was occupied until 1530, around the time of the Spanish invasion. These amended dates would place Pachacuti's conquest of the region much earlier than historical accounts indicate. Read the original scholarly article about this research in Antiquity. To read about an enigmatic site in Peru's Pisco Valley popularly known as the "Band of Holes," go to "An Overlooked Inca Wonder."