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Harvard student helps crack mystery of Inca code

Manny Medrano displays a model of khipu knots, an information system that the Inca used to tally and record data.Jon Chase/Harvard Staff Photographer

It’s a mystery that has left many scholars flummoxed.

For all the achievements of the Inca Empire, including a massive roadway system, sophisticated farming methods, and jaw-dropping architecture, it was the only pre-Columbian state that did not invent a system of writing.

Instead, the Inca, whose civilization originated in Peru and grew to include peoples and cultures all along the west coast of South America from 1400 to 1532, relied on knotted strings to encode information, a system so complex that scholars still struggle to make sense of it.

Which is what makes the work of Harvard student Manny Medrano all the more remarkable. The young student provided new insight into how the Inca recorded information by analyzing the colors and the direction of the knots placed on the strings, known as khipus.


The discovery could be a first step to unlocking far more Inca history.

Three years ago, freshman Medrano was working as a research assistant for Gary Urton, the Dumbarton Oaks Professor of Pre-Columbian Studies and chair in the Department of Anthropology at Harvard University. Medrano, then just 19, decided to spend his spring break analyzing the data from six khipus that were found in the collection of an old Italian count who’d lived in Peru.

The Inca used khipus — the colorful, three-dimensional string systems — as record-keeping devices to tally census data, inventory resources, and record narratives such as royal histories, myths, and songs.

Anthropologists believe that the codes would contain insights into the Inca’s way of life, if they could be broken. Furthermore, it would be the first history of the Inca told from the perspectives of the indigenous peoples themselves.

“The only history we have of the Inca Empire are ones that were written by Spaniards after they conquered the Incas,” said Urton. “And those have all sorts of problems about the Spaniards writing from their own viewpoint and with their own prejudices. It seemed to me that the khipus represented the Incas’s own histories of themselves.”


Alas, there is no Rosetta Stone for khipus, no translation for what the patterns of knots represent, and no match between the Spanish documents and the khipus themselves. What did exist was the Harvard Khipu Database Project, which Urton established in 2002 to collect all known information about khipus into one centralized repository.

Medrano set to work. Though he was most interested in studying mathematics and economics, he also had a strong interest in archeology.

“We think of language as either spoken or written down,” Medrano said. “But the khipu really takes that and breaks that boundary and makes language something that can be felt, something that can be touched, and something that can be handled.”

He made graphs and compared the knots on the khipu to an old Spanish census document from the region when something clicked.

“Something looked out of the ordinary in that moment,” Medrano said. “It seemed there was a coincidence that was too strong to be random.”

He realized that, like a kind of textile abacus, the number of unique colors on the strings nearly matched with the number of first names on the Spanish census.

For example, if there were eight “Felipes,” all were indicated by one color, while “Joses” were indicated by another color.

“There were so many different combinations of colors, whether solid colors or two colors spun together,” Medrano said. “This looked like there was enough diversity in here to encode a language.”


The khipus were similar and came from a burial site in a river valley on the north coast of Peru. Urton had previously discovered that the Spanish document referenced 132 taxpayers in a village.

Altogether, the six khipus had 132 six-cord groups.

As a result of Medrano’s discoveries, Urton and Medrano produced a paper, which will be published in the academic journal Ethnohistory in January. Medrano, now a junior, is the lead author of the article, “Toward the Decipherment of a Set of Mid-Colonial Khipus from the Santa Valley, Coastal Peru.”

The paper states that what Medrano found is “the first instance of ‘reading’ information from khipu attachment knots.”

Medrano plans to continue his research. He has decided to major in applied mathematics and minor in archeology.

“There are hundreds of khipus that could encode stories and also hundreds if not thousands of Spanish documents from the period that also contain transcribed stories,” Medrano said. “But, we need a link [to connect them.]”

“Being able to look at the past not just as Indiana Jones or trying to discover a golden idol in a cave,” Medrano said, “but to help the process of getting history told from the perspective of the people who have been conquered.”

Cristela Guerra can be reached at cristela.guerra@globe.com. Follow her on Twitter @CristelaGuerra.