# Mathematician:Leonardo Fibonacci

## Mathematician

Italian mathematician.

One of the most important figures in the history of the development of mathematics.

Wrote the highly influential and important Liber Abaci in which he discussed the Hindu-Arabic number system and its practical applications.

Most famous for the Fibonacci numbers. The number sequence itself was known to Indian mathematicians as early as the $6$th century, but it was Fibonacci's Liber Abaci which made them well-known throughout Europe.

Italian

## History

• Born: c. 1170
• Died: c. 1250

## Theorems and Definitions

### Concepts derived from Fibonacci numbers

Results named for Leonardo Fibonacci can be found here.

Definitions of concepts named for Leonardo Fibonacci can be found here.

## Notable Quotes

When my father, who had been appointed by his country as public notary in the customs at Bugia acting for the Pisan merchants going there, was in charge, he summoned me to him while I was still a child, and having an eye to usefulness and future convenience, desired me to stay there and receive instruction in the school of accounting. There, when I had been introduced to the art of the Indians' nine symbols through remarkable teaching, knowledge of the art very soon pleased me above all else.
-- $1202$: Liber Abaci

## Critical View

Fibonacci was by far the greatest European mathematician of the Middle Ages.
-- 1997: Donald E. Knuth: The Art of Computer Programming: Volume 1: Fundamental Algorithms (3rd ed.)

## Also known as

Leonardo Fibonacci also known as Leonardo of Pisa, Leonardo Pisano, Leonardo Bonacci or usually just Fibonacci.

The name Fibonacci comes (posthumously) from filius Bonacci, that is: son of Bonacci (his father was nicknamed Bonacci, meaning good-natured or simpleton). These were the days before official surnames. The name is not recorded before the $18$th century and may have been invented as late as then.

An ironic soubriquet.

## Linguistic Note

Fibonacci is an Italian surname whose pronunciation is something like Fib-bo-nat-chi, or Fib-bo-nar-chi, according to taste.

Avoid pronouncing it Fie-bo-nac-ky.