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 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 which made them well-known throughout Europe.

Nationality
Italian

History

 * Born: c. 1170
 * Died: c. 1250

Theorems and Definitions

 * Fibonacci numbers
 * Brahmagupta-Fibonacci Identity (with ) (also known as Diophantus's Identity)
 * Practical Number (discussed at length in )

Concepts derived from Fibonacci numbers

 * Fibonacci Polynomial
 * Fibonacci Prime
 * Fibonacci String, also known as a Fibonacci Word
 * Fibonacci Number System
 * Fibonacci Nim
 * Reciprocal Fibonacci Constant
 * Pisano Period

Publications

 * 1202: (Book of Abacus or Book of Calculation) which introduced the Arabic numerals to the Western world. Sometimes (possibly erroneously) called Liber Abbaci.
 * 1220: Practica Geometriae, a compendium on geometry and trigonometry.
 * 1225:, solutions to problems posed by a friend of his, Johannes of Palermo.
 * 1225: (The Book of Squares) on Diophantine equations, in which in particular the Brahmagupta-Fibonacci Identity is discussed.
 * Di minor guisa, on commercial arithmetic (lost)
 * A commentary on Book X of (lost)

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.
 * -- $1202$:

Critical View

 * Fibonacci was by far the greatest European mathematician of the Middle Ages.

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.