Leonardo Fibonacci | Biography

Fibonacci was born in Pisa, Italy, which at that time was a great mercantile and trading city. Fibonacci's father was administrator of Pisa's trading center in Algeria, and young Leonardo often accompanied his father on trips there. It is believed that Fibonacci spent much of his youth in the Algerian town of Bougie and was schooled in the art of calculation with Hindu-Arabic numerals. Later, Fibonacci traveled to Egypt, Syria, Greece, and Sicily, but remained in North Africa for extended periods. He returned to Pisa about 1200.

Fibonacci, also known as Leonardo Pisano, or Leonardo of Pisa, occasionally used "Leonardo Bigollo," a surname which could mean either "traveler" or "blockhead." Fibonacci may have used the name to indicate he was a great traveler. However, it has also been suggested that his contemporaries considered him to be a blockhead for his use of the Hindu-Arabic numbers, and that Fibonacci used the name to show them just what a blockhead could accomplish.

After settling in Pisa, Fibonacci became convinced of the superiority of the Hindu-Arabic system and wrote Liber abaci, or "Book of the Calculator," which he published in 1202 then revised in 1228. A thorough treatment of algebraic calculation that strongly supported the Hindu-Arabic system, the book consisted of four major sections. In section one, Fibonacci refers to Roman numerals and finger computation. In the same section he explains the uses of Hindu-Arabic numerals, the value of positional notation, and introduces a bar symbol for fractions.

In sections two and three, Fibonacci offers various problems and solutions of an algebraic nature and introduces the interesting sequence of numbers 1, 1, 2, 3, 5, 8, 13..., x, y, x + y. Known as the Fibonacci sequence, each term after the first two are obtained by adding the preceding two terms together. The Fibonacci sequence was later found to have many significant applications in the world of nature. For instance, spirals formed by the centers of daisies, pine cone scales and leaves, generally have two sets of spirals--one clockwise, one counterclockwise. The number of spirals are adjacent terms in the Fibonacci sequence. For example, in pine cone scales, five spiral one way, eight the other. In the United States, a Fibonacci Society exists which studies the properties of this mysterious sequence of numbers.

Fibonacci's life and activities after the year 1225 are obscure. He won a mathematics tournament in 1225 at the court of Pisa and is assumed to have spent the remainder of his life there until his death in 1230. Liber Abaci remained a important book during the next two centuries and played an important role in spreading the Hindu-Arabic numeral system throughout Europe.