Machu Picchu Even Older Than Previously Thought, New Dating Methods Show


Tom Hale


Tom Hale

Senior Journalist

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist

Machu Picchu.

Machu Picchu can be found between the Peruvian Andes and the Amazon Basin at a ridge some 2,400 meters (7875 feet) above sea level. Image credit: Lukas Uher/

Machu Picchu, the iconic Inca citadel perched in the llama-filled mountains of Peru, appears to be older than most previously realized, according to a new study.

Most archaeologists believe that Machu Picchu was built as an estate for the Inca emperor Pachacuti. If the historical records of the Spanish colonialist are anything to go by, the emperor came to power in 1438 CE, indicating the citadel was constructed at some point between 1440 and 1450 CE depending on how long it took for his army to conquer the local region.


However, new dating reveals the site was likely settled at least two decades before this. As reported in the journal Antiquity, archaeologists used accelerator mass spectrometry dating on the skeletal remains of 26 people found at the three cemeteries in Machu Picchu during excavations at the site in 1912. This revealed that Machu Picchu was occupied from around 1420 to 1530 CE, just over 20 years before previously thought. 

Machu Picchu 1911
Researchers at Machu Picchu in 1911, one year before the excavations that revealed the remains dated in this study. Image supplied by Burger et al., 2021, Antiquity 

“Machu Picchu is among the most famous archaeological sites in the world, but until now estimates of its antiquity and the length of its occupation were based on contradictory historical accounts written by Spaniards in the period following the Spanish conquest,” Professor Richard Burger, lead author of the research from Yale University, said in a statement sent IFLScience.

“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,” continued Professor Burger.

Machu Picchu can be found on a fault line between the Peruvian Andes and the Amazon Basin some 2,400 meters (7,875 feet) above sea level. It consists of around 200 structures, including ceremonial structures and a royalty area for the nobility, as well as residences for workers and hundreds of slated terraces used for agriculture. 

Machu picchu
Machu Picchu in 2009, excavated and ready for tourists. Image credit: Pedro Szekely CC BY-SA 2.0

Following the Spanish conquest of the Inca Empire in the late 16th century, Machu Picchu laid in the mountains undisturbed for centuries, eventually falling to ruins and becoming engulfed in vegetation. The modern world didn't become aware of this majestic site until the early 20th century when it was rediscovered by American archaeologist Hiram Bingham in 1911 and later excavated.

It's widely believed the complex was constructed as an estate for emperor Pachacuti, an important figure in the story of the Inca. As an ambitious and famed ruler, he conquered a significant amount of territory around present-day Peru, paving the way for the Inca empire to grow across the western coast of South America until the Spanish conquests from 1532 CE.

Given that Machu Picchu appears to have existed 20 years before commonly thought, it also suggests that our timeframe of Pachacuti’s rule may also be off. Ultimately, this challenges whether we should blindly trust the records of the Spanish invaders to piece together the story of the Pre-Columbian era.

“The results suggest that the discussion of the development of the Inca empire based primarily on colonial records requires revision,” said Professor Burger, “modern radiocarbon methods provide a better foundation for understanding Inca chronology than the contradictory historical records.”

 This Week in IFLScience

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