The Revolution That was 1 2 3 4 5 6 7 8 9 and 0

“Novem figure indorum he sunt 9 8 7 6 5 4 3 2 1 Cum his itaque novem figuris, et cum hoc signo 0, quod arabice zephirum appellatur, scribitur quilibet numerus, ut inferius demonstratur.”

“The nine Indian figures are 9 8 7 6 5 4 3 2 1. With these nine figures and with the symbol 0, which the Arabs call zepher, any number can be written, as will be demonstrated. “

-The opening sentence of Chapter 1 of Leonardo Fibonacci’s Liber Abaci (The translation is mine)

The Liber Abaci, which translates as “The Book of Calculations” was published in 1202 and in many ways changed the course of western history. This may sound like hyperbole, but let me explain. Today we take for granted that:

479

+

  953  

1450

In 1202, prior to the adoption of the “Arabic Numerals,” as they came to be called, this calculation would have been done with Roman Numerals:

CDLXXIX

+

  CMLIII  

MCDL

The benefits of the Arabic system are self explanatory.

Fairly simple math was very complicated and difficult. This new system not only changed how we represented the number, it democratized math.

While most people had a basic understanding of smaller numbers and could do everyday arithmetic, once the number got too large, you would have to go to a specialist.  In the middle ages any high value math was only done by trained professionals. These individuals would do their calculations with a large table abacus and were generally found on the banks of the river to help traders do their sale calculations. These individuals would also work as money and currency traders (Italy alone had more than 20 currencies at that time).  If you needed someone to change money you would go to the “bank” of the river, and that name stuck.  These calculations often took quite some time and a customer would often have to take the bankers calculations at their word.

Fibonacci changed that.  His book aimed to show that the Arabic Numerals (which he correctly called Indian) were a better way of representing numbers. His book makes this argument convincingly. The entire book serves as an introduction to using this number system.

Fibonacci is more often remembered today for the “Fibonacci number sequence:” 0,1,1,2,3,5,8,13,21,34,55,89,144… (The next number is the sum of the previous two.) This number sequence was also introduced, but not invented, in this book.

At a young age, Fibonacci visited North Africa with his father and witnessed the Arabic traders using the simplified Indian counting system,  and he understood that this not only made math much easier, it made transactions much faster. Checking work also became simple, and advanced calculations also became much more manageable.  This revelation became the Liber Abaci. This was a case of the “right place at the right time.”  The book was published in Italy, the center of European trade. It was written in Latin, the language of learning in Europe. The book was an instant hit.

When people began to realize how much simpler using Arabic Numerals were over using Roman Numerals, the new number system became widespread. Within a few decades, Arabic Numerals became standard in Italy, and over the course of the 1200s, they became standard in Europe.

There was some initial pushback though.  Some guilds realized that if the new system was adopted, they, who specialized in working in the old way, would be out of a job. These guilds exerted their political pressure and quite a few city states outlawed the new system in commerce.  This did not last and the new system became the standard.

It was in the 1200s that Italy became the banking capital of the Europe. Bankers and merchants over time became more powerful, more learned, and they began investing in their culture. By the 1300s many of these merchant families (e.g. the Medici Family) were the government leaders, and their investment in learning and art jump-started a movement that became the Italian Renaissance.

It’s funny how a few little numbers changed the world.