Roots : {How the Fibonacci Sequence Got Its Name}

Leonardo Fibonacci was born into a mercantile family in Pisa around 1170.  His father was appointed to a post in the Algerian city of Bougie when Leonardo was a young man, and so he accompanied his father there and began computational studies under a Muslim schoolmaster.  In this way he became familiar with the Indo-Arabic numeration system and computational techniques, including algebra.  In later years, Fibonacci continued his study of various systems of arithmetic during business trips to Constantinople, Egypt, France, Greece, and Syria, and even lived for a time at the court of the Roman Emperor, Frederick II, where he frequently debated with the emperor and his philosophers about such scientific topics.  In 1202 Fibonacci published his first work, Liber Abaci (The Book of the Abacus) which introduced the Indo-Arabic mathematical system to the European world, demonstrating its strengths and arguing for its adoption over the Roman system then in use.  This first book included the following problem concerning the reproduction pattern of rabbits:

Suppose there are two newborn rabbits, one male and the other female.  Find the number of rabbits produced in a year if:

• each pair takes one month to become mature;
• each pair reproduces a mixed pair every month, from the second month on; and
• no rabbits die during the course of the year.

The results of this problem look like:

	month 1	month 2	month 3	month 4	month 5	month 6	month 7	month 8
numbers of pairs	1	1	2	3	5	8	13	21

This pattern of numbers (1,1,2,3,5,8,13,21…..) is the beginning of the Fibonacci Sequence, thus named in 1876 by the French mathematician Francois-Edouard-Anatole-Lucas after the author of the Rabbit Problem. 


Sources use on this page: Koshy, Thomas. See bibliography.