Professional historians have long known that the “Dark Ages” — roughly, the period between 500 to 1000 — was not a time of ignorance or superstition, but involved a range of scientific, economic, and cultural advances. For that reason, it’s always nice to see a work of popular history set the record straight, as Nancy Marie Brown does in her new book, The Abacus and the Cross: The Story of the Pope Who Brought the Light of Science to the Dark Ages. While she focuses principally on the impressive Pope Sylvester II — the leading mathematician and astronomer of the time — she also rebuts the broader stereotypes surrounding the era.
The popular picture of the Dark Ages is wrong. The earth wasn’t flat. People weren’t terrified that the world would end at midnight on December 31, 999. Christians did not believe Muslims and Jews were the enemy. The Church wasn’t anti-science.
In the Dark Ages, contrary to what most people think, science was central to the lives of monks, kings, emperors, and even popes. It was the mark of true nobility and the highest form of worship of God.
As for Pope Sylvester II himself (formerly, Gerbert of Aurillac):
A professor at a cathedral school for most of his career, Gerbert of Aurillac was the first Christian known to teach math using the nine Arabic numerals and zero. He devised an abacus, or counting board, that mimics the algorithms we use today for adding, subtracting, multiplying, and dividing. It has been called the first counting device in Europe to function digitally — even the first computer. In a chronology of computer history, Gerbert’s abacus is one of only four innovations mentioned between 3000 BC and the invention of the slide rule in 1622.
Like a modern scientist, Gerbert questioned authority. He experimented. To learn which of two rules best calculated the area of an equilateral triangle, he cut out square inches of parchment and measured the triangle with them. To learn why organ pipes do not behave acoustically like strings, he built models and devised an equation. (A modern physicist who checked his result calls it ingenious, if labor-intensive.)
Gerbert made sighting tubes to observe the stars and constructed globes on which their positions were recorded relative to lines of celestial longitude and latitude. He (or more likely his best student) wrote a book on the astrolabe, an instrument for telling time and making measurements by the sun or stars. You could even use it to calculate the circumference of the earth, which Gerbert and his peers knew very well was not flat like a disc but round as an apple.