In his project "Empire of String: Unravelling the Enigma of Inka Khipus," 2025 Harvard Horizons Scholar Mack FitzPatrick is immersing himself in the complex record-keeping system of khipus: intricate knotted cord devices that served as the administrative backbone of the Inka civilization.
The Inka Empire, the largest in the pre-Columbian Americas, is renowned for its impressive engineering feats, including an extensive road network and monumental architecture. Although the Inkas did not have a traditional writing system, they recorded information using a unique method: khipus. These knotted cords were essential tools for communication and record-keeping. Through meticulous structural analysis and documentation, FitzPatrick seeks to uncover the meanings encoded in khipus beyond their numerical knots. FitzPatrick’s project not only aims to advance archaeological knowledge but also seeks to reframe public understanding of the Inka Empire's complex administrative capabilities. By preserving and interpreting khipus, he hopes to reveal a more nuanced history of the Andean civilizations, illuminating the enduring legacy of their cultural innovations for contemporary audiences, as well as a powerful Indigenous perspective on Andean history—one distinct from narratives provided by Europeans.
The Inka rose to power in the 15th century. And in less than 100 years, they built the largest Indigenous empire ever realized in the Americas. At its height, this empire spanned thousands of kilometers across the Andes, encompassing millions of people, animals, and resources. The Inka built an extensive road network across deserts, mountains, and jungles. They perfected terraced farming and constructed precise stone architecture.
Yet, remarkably, the Inka built and managed this massive empire without a conventional written script. Consider just how many text messages and emails you send every day, just to manage your own life. Now, imagine running an entire empire, no email, no text message, no conventional form of writing.
Rather than pen and paper, the Inka relied on knotted cords, like these, called khipu. Now, we know the Inka used khipu for a wide range of numerical purposes, like census counts and storehouse inventories. But we also have early Spanish colonial accounts that describe khipus that encoded narratives, like songs, histories, and stories. Today, much of how khipus actually functioned remains a mystery. And so my research seeks to unravel this enigma. But let's just start with a single cord.
Thanks to past scholarship, we know how Inka khipus encoded numbers. Knots are arranged in groups along the cord in powers of 10, with the ones positioned furthest down the cord. Now, the cord you see behind me has the number 1,636. It's represented by one knot in the thousands place, highest on the cord, six overhand knots in the hundreds place, three overhand knots in the tens place, and a special kind of knot, called a long knot, made here with six turns, in the ones place, where each turn represents one unit.
Now, you may also notice an extra knot at the end of the cord here. This knot does not add to the value of the cord, but instead, is there to keep it from unraveling. Now, while we can confidently read numbers like these off of khipus, we don't always know what they represent. Number of people? Ears of corn? Harvard's founding date? We're not always sure. And even more perplexing, some khipu cords have no knots at all. This has led researchers like myself to look for non-numerical signs in Inka khipus.
Notice that the cord behind me is more than just a string with knots. It can be attached to other cords in various ways. It has color and pattern, and the body of the cord can be twisted counterclockwise or clockwise, which we call S and Z twisting, respectively. Although I'm not the first to make these observations, new methods allow me to collect higher resolution data than ever before. Rather than relying on my eyes alone, I use a Pantone system to encode colors more accurately. Instead of simply recording the external twist of the cord like we just saw, I also record the entire internal structure of each cord, which may give us a glimpse at how and perhaps by whom each cord was made.
For my dissertation then, I spent hundreds of hours meticulously documenting khipu attributes like these in spreadsheets. And by converting khipus to spreadsheets, I'm able to conduct large-scale analysis while simultaneously aiding in the preservation of these fragile objects. But how can these other structures, like a khipu cord's attachment knot, be used to encode data? Well, for one answer, we can turn to a set of possible Rosetta khipus.
In the early 2000s researchers identified a Spanish colonial document and a set of six khipus that appeared to record the same taxation event. Both the khipus and the document recorded the total amount of tax payers and the total amount of tax owed by this community. Later, in 2018, my colleague Manny Medrano hypothesized that the two ways you can attach a khipu cord could be used to encode the Andean social structure of moiety, which divides communities into two social halves.
Now, building on these insights, I wanted to see just how far I could take the Rosetta khipus. And by analyzing the khipu data alongside the document, I was able to reconstruct a detailed set of social and political hierarchies for this community. Notably, these hierarchies were absent from the Spanish document, but instead preserved in the khipus.
I began asking myself, what aspects of khipus and of the past are we missing out on through our current methods? I realized we'd narrowed our perspective, focusing solely on deciphering khipus. We did not take seriously the materiality and multidimensionality that khipus had to offer us. As children, we learned that reading and writing go hand in hand. Yet, for decades, we've been trying to read khipus without fully understanding how they were written.
So I decided to flip the process on its head, working backwards to understand how khipus were made, who made them, and what this can tell us about their use. I thought, what better way to get inside the mind of a khipu maker than to become one myself? This has meant shifting my analysis between analyzing archaeological specimens and creating my own khipu replicas. And through this embodied practice, I've gained a better appreciation for the structures found in khipus and for the types of data they could encode.
Perhaps the most interesting insight for me has been realizing that for conventional writing, any medium will do, paper, stone, wood, you name it. These are all simply vessels for the information you wish to convey. But for khipus, the information and the medium are one in the same. But this is something you really have to experience for yourself.
Perhaps you've noticed by now, the bookmarks in your programs are actually khipu cords. I want you to take out these cords right now. Go ahead, take them out. I want you to feel the materiality of the cord in your hand. Feel the tactile nature of the data it encodes and compare this to the flatness of your program.
Now, I want us to try adding some new information to this cord. I'd like everyone to try and tie a simple overhand knot on the topmost portion of your cord that's furthest from that end knot we talked about earlier. Go ahead, try to tie it. And notice that in doing so, in adding this new knot, this new information, you have to physically alter and physically manipulate the very structure of the material in your hands.
Now, I must confess, while this talk began with the Inka, khipu technology has a much deeper history in the Andes. And even today, forms of this technology persist. Deciphering khipus then allows us to peer into the pre-Columbian past, while simultaneously having real implications for contemporary Andean communities, working to preserve and revitalize khipu traditions. For now, my work, along with that of others, seeks to give voice to the histories encoded in these cords. But it's truly my hope that one day soon, the khipus will speak for themselves. Thank you.