Machu Picchu is decades older than researchers previously thought, according to a new study

• Machu Picchu was occupied decades earlier than previously believed, researchers say.
• The study suggests that the citadel was used from about 1420 to 1530, decades earlier than previously believed.
• Researchers led by Yale archaeologist Richard Burger used an advanced form of radiocarbon dating to make the discovery.

Machu Picchu, the 15th century Inca citadel in the Eastern Cordillera of southern Peru, was occupied decades earlier than was previously believed, researchers said Tuesday.

According to a press release published Tuesday by Yale Univesity, a team led by Yale archaeologist Richard Burger and researchers from several other US institutions used an advanced form of radiocarbon dating called accelerator mass spectrometry to date human remains found in the early 1900s.

The findings were published in the journal Antiquity.

The study suggests that the citadel was in use decades earlier than previously thought from about 1420 to 1530, according to the press release. Based on historical documents, scholars previously believed Machu Picchu was erected between 1440 and 1450.

"Until now, estimates of Machu Picchu's antiquity and the length of its occupation were based on contradictory historical accounts written by Spaniards in the period following the Spanish conquest," Burger said in the press release.

"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, giving us a clearer picture of the site's origins and history," he added.