"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 ze

"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.)"