Andrew Bair is set to graduate from Harvard Griffin GSAS in May 2026 with a PhD in anthropology. He talks about his research challenging the accepted chronology of Irish settlement in the Middle Ages, how his study of archaeology and computer science at Columbia led him eventually to Harvard Griffin GSAS, and about growing up in a curious family and literally growing out of his dream of being an astronaut.
Expanding the Window
My dissertation research focuses on ring forts, which are the most numerous archaeological site type in Ireland. There are roughly 45,000 of them scattered across the island. When you walk through the Irish countryside, you see these circular enclosures everywhere. Conventionally, they are dated to a very narrow window between approximately AD 600 and 1000.
This chronology was largely established because the sites align so well with early Irish legal texts and histories. Ireland has a remarkable corpus of textual sources from the early Middle Ages that describe an agrarian, middle-class society living in these circular forts. The archaeological evidence for this date range was also so strong that by the time I came onto the scene as a scholar, it was more or less a "known fact" that these sites belonged to those four centuries.
But there’s a reason why few people have challenged this timeline: excavation is slow, expensive, and destructive. And once you dig a site, it’s gone forever; you can never put things back exactly the way you found them. You only get one shot.
Because of this, archaeologists are often disincentivized from studying "boring" rural ring forts. If you are a young Irish archaeologist and you have a limited amount of time in your career, are you going to spend your life excavating nine "middle-class" ring forts, or are you going to excavate the site where historical documents suggest a king lived and there might be amazing artifacts? Why take a risk on a potentially boring site when you have a better chance of finding something new and exciting at the largest and best-preserved examples?
The "Invisible People" and Para-Excavation
I wanted to test this established chronology because I suspected these sites had longer histories than we realized. My theory was that if we started looking at ring forts more closely, we might find the "missing centuries" of Irish archaeology. The Iron Age—which comes right before the early Middle Ages—is famously said to have been inhabited by "invisible people" because their settlement sites are so hard to find. Similarly, the eleventh and twelfth centuries have proven similarly hard to find. I once asked an archaeologist where he thought people were living in the twelfth century, and he joked, "On the moon."
I decided to use a method I call "para-excavation" to solve this. Instead of a full-scale excavation, I combined geophysical surveys with high-precision radiocarbon dating of very small samples. This allowed me to survey nine sites in my region in Western Ireland.
By using GPR and a technique called magnetometry, I could visualize the internal structures of the forts without destroying them. Then, I could target very specific areas to extract tiny pieces of burnt wood or organic material for chronometric dating. Radiocarbon dating gives us an absolute calendar date with a small error range—say, plus or minus twenty-five years. It tells us exactly when a piece of wood was dropped by someone and covered by soil.
My theory was that if we started looking at ring forts more closely, we might find the "missing centuries" of Irish archaeology.
What I found was fascinating. While many sites were indeed occupied between AD 600 and 1000, the spike in activity in my study area was much later than the conventional model suggests—around AD 750 to 800. More surprisingly, I found evidence of Iron Age activity on some sites, suggesting they were being used much earlier than the textbooks allowed. The sites saw continued use in the 11th and 12th centuries as well, and even through the 17th century!
From Computer Science to County Roscommon
I went to Columbia University for my undergraduate degree. I had a long-standing interest in archaeology, but decided to explore a wide range of subjects during my first year. I took general chemistry, art history, and all kinds of classes just for fun. Eventually, I took an archaeology class with Professor Zoe Crossland. She saw how interested I was in the topic and helped me find a field school for that first summer.
I ended up majoring in archaeology and minoring in computer science (CS). When I graduated in 2017, it was the "boom days" of computer science. At Columbia, it seemed like everyone was doing CS because it was either that or banking if you wanted a high-paying job. But I wasn’t doing it for career reasons; I just thought it was interesting and fun. I liked the logic of it. Of course, now all my coding skills are completely antiquated, but I really enjoyed the challenge at the time.
My path to Ireland was entirely accidental. My advising dean at Columbia, Chad Gifford, noticed I was an archaeologist and asked if I wanted to do archaeology with him over the summer. I said sure and joined him in 2016 for a project called "Castles in Communities" in Ballintober, County Roscommon. I started there as a student, but I eventually worked my way to leadership. Today, I am one of the co-directors of the project.
While I was in Ireland that first summer, I happened to meet University of Denver Archaeology Professor Lawrence Conyers, who was friends with one of the guys running the project. Larry is the leading expert in ground-penetrating radar (GPR), which has since become my specialty. GPR is a technique of geophysical archaeology that harnesses the physical and chemical properties of the Earth to visualize what is buried without having to dig it up. Most archaeology is found in the top few meters of soil, so if you can map it before you ever break ground, it’s a huge advantage.
Larry invited me to be his student at the University of Denver, where I spent two years getting my master’s degree. We traveled across the American Southwest and Central America, and I received intense training in near-surface geophysics. I arrived at Harvard GSAS with that specialized skill set, having already been embedded in the Irish project for several years.
Curious about What’s Underground—and in Space
I grew up in Philadelphia in a family that was not academic but was certainly creative and curious. My father is an emergency room doctor, and my mother is a composer for musical theater. When I was a child, she actually wrote an adaptation of Romeo and Juliet for my elementary school’s annual production. It was a massive undertaking—she wrote the music, the book, and the lyrics. It was about cats and mice, so it featured the “Mouseagues” and the “Catulets.” It was a huge hit, and she ended up pursuing composing more seriously down the line. She still does it today.
I was drawn to archaeology from a young age. I still remember receiving a gift of an Egyptian scarab sculpture when I was maybe four years old. I was also deeply interested in dinosaurs, and for a while, I wanted to be an astronaut. Unfortunately, I am six feet six inches tall, too big for the space program.
But I have always been curious about the past. I also liked science quite a bit, particularly the physical and natural sciences, as well as history and languages. Archaeology is a really nice knitting together of all those interests. I remember my mom taking me to an excavation at an old mill in Philadelphia when I was a kid. It was an open archaeology day, and I spent the time working the screens—sieving soil and sediment to pick out artifacts the excavators might have missed. Looking back, that was my first real taste of the field, though I didn't know it would become my career.
I found evidence of Iron Age activity on some sites, suggesting they were being used much earlier than the textbooks allowed. The sites saw continued use in the 11th and 12th centuries as well, and even through the 17th century!
Embracing the Complexity of the Past
One of the major realizations of my work is that the way we categorize the past—sorting things into neat baskets like "the Iron Age" or "the Middle Ages"—tells us more about ourselves in the present than it does about the people who lived back then. People in the past didn't wake up and think they were living in the Middle Ages. When we focus too much on these labels, we miss the more complicated and compelling stories of the places themselves.
I’m defending my dissertation in two weeks and hope to graduate in May. I didn’t know exactly what I had when I started this project, but these new tools allow us to celebrate and embrace the complexity of the past rather than trying to simplify it. I plan to publish my findings this fall and eventually turn this research into a book.
