Mad about Science: Curious Medieval Sciences

By Brenden Bobby
Reader Columnist

You’ve heard me say it a hundred times: the medieval period gets a bad rap. Littered with stories of gluttonous lords, illiterate peasants and noble knights slaying dragons at the behest of fair maidens, one is left to wonder what scholars of 3024 may think of our current age. Will they believe that we were only able to view the world through the screen of our phones and that no other forms of communication existed during this period? Perhaps they will think we worshiped influencers as gods and only knew how to gather food using the labors of a vest-wearing servant class forced to fetch our desires and load them into our iron chariots.

Science during the medieval period seems like a crazy idea, and the common misconception is that scientific advancement virtually halted until the Renaissance. This is a complete fallacy and anyone who’s ever truly looked at how a crossbow works or how a cathedral was constructed would know this period of history had some seriously smart folks designing things that survived to this day. Can we say the same about our first iPhone?

A westerner and an Arab learning geometry in the 15th century, by an anonymous painter. Courtesy of Creative Commons.

Pope Sylvester II

Was math your weakest subject in high school? Just imagine if you had to divide CCLVII by XXV. Thanks to Gerbert of Aurillac, later known as Pope Sylvester II, you never had to find the remainder of Roman numerals.

Gerbert of Aurillac was a scholar, clergyman and eventual pope who studied mathematics in Arabic Spain in the mid-to-late 900s C.E. Muslim scholars had been using a version of the 10 digits we use today for quite some time, while Roman numerals remained en vogue throughout Europe for almost a thousand years. Aurillac was able to calculate large numbers rapidly with an abacus using Arabic digits and very quickly outpaced his contemporaries in the Catholic Church that were still stuck using antiquated numerals.

Interestingly, the Abacus didn’t actually use 0, but instead used gaps where a 0 would land. If this sounds confusing, you’re absolutely right — 867-53_9 just doesn’t have the same ring to it, but in a gridded abacus it made considerably more sense at the time. This abacus was the basis for how many of us learned to add and subtract in elementary school, and it became an essential tool for both the church and nobility to track their growing wealth and plan for the future.

Math, circles, spheres and clocks

Everyone thinks that people in the medieval period believed the world was flat. This is one of the most common misconceptions of the era. The spherical nature of the world has been known measured with remarkable accuracy since as early as 240 B.C.E., when Eratosthenes and his assistant measured the circumference of the Earth by its shadow cast on the moon from two locations: Alexandria and Syene. This knowledge wasn’t simply discarded after the collapse of the Roman Empire and the subsequent so-called Dark Ages. In fact, the medieval Catholic Church was well aware of both the curvature and size of the Earth — so accurately that it managed to figure out rough time zones throughout Europe.

In the early 1200s, the scholar Johannes de Sacrobosco (also known as John of Holywood) wrote a manuscript titled De Sphaera Mundi, or On the Sphere of the World, that is cited to this day. In it, Sacrobosco stated how ships disappear into the curvature of the horizon and how constellations appear differently from various spots on the globe. His treatise was so comprehensive that it was used as a teaching tool for four centuries. While the book was primarily about the universe being spherical in shape, it also clearly describes the Earth as being spherical as well.

Much of the “people believed the Earth is flat in the Middle Ages” myth likely has its roots in the outdated belief of geocentrism, or the idea that the universe revolves around Earth. 

This was believed to be true as early as the fifth century B.C.E., until the idea of heliocentrism — or the universe revolving around the sun — was first proposed by Nicolaus Copernicus in 1543. This was hotly debated, particularly in the Catholic Church, of which Copernicus was a clergyman, even after the telescopic observations and proof presented by Galileo Galilei in the early 1600s.

Galileo was famously sentenced to lifelong imprisonment for heresy in 1632. This sentence is an oversimplification of events that transpired throughout Galileo’s life, and while it is often cited as the “ignorance” of the Catholic Church and the Inquisition, Galileo was also quite aggressive and inflammatory with a number of his comments toward supporters of geocentrism as well as conflicts with Pope Urban VIII. 

Ultimately, political pressures from the Inquisition damned Galileo to imprisonment under house arrest, yet he still managed to smuggle mathematical findings out of Italy to neighboring countries. 

By the 1700s, astronomers and mathematicians like William Herschel presented the idea that heliocentrism and geocentrism were both wrong. As it stands currently, we know that the sun orbits Sagittarius A*, a supermassive black hole at the heart of the Milky Way galaxy 4.297 million times more massive than the sun. Someone probably has an idea of where the center of the universe is, but I sure couldn’t tell you.

These are just a couple of the interesting examples of surprising math from the medieval period. In the future, we’re going to look at more exciting developments largely involving weapons and projectiles.

If you’ve followed this article for any amount of time you’re very familiar with my love of all things pointy and dangerous.

Stay curious, 7B.