Leonardo Fibonacci Biography

Leonardo Pisano, now better known by his nickname Fibonacci, also sometimes used the name Bigollo, which may mean good-for-nothing or a traveller. He was born in Pisa, Italy around 1170. At the time, Pisa was an important commercial town and had links with many Mediterranean ports. He was the son of Guilielmo Bonacci, a diplomat for the Republic of Pisa. Guilielmo was responsible, beginning around 1192, for directing the Pisan trading colony in Bugia, Algeria where he represented the merchants of the Republic of Pisa. Bugia, later called Bougie and now called Bejaia exported wax candles. The French word for candle, Bougie, is derived from the Algerian port’s name.

Some time after 1192, Guilielmo Bonacci brought Leonardo with him to Bugia. Leonardo received a North African education under the Moors, and was taught their style of mathematics. Guilielmo intended for his son Leonardo to become a merchant and so had arranged for his education in calculational techniques, especially those involving the Hindu-Arabic numerals which had not yet been introduced into Europe. Later, Leonardo was assigned to do business for the Pisan republic and he travelled extensively around the Mediterranean coast. He was sent on trips to Egypt, Syria, Greece, Sicily, and Provence. He took the opportunity offered by his travel abroad to study and learn the mathematical techniques used in these various regions. He would have met with many merchants and thereby discovered their systems of doing arithmetic.

Around 1200, Fibonacci ended his travels and returned to Pisa. On returning home he began to work on his own mathematical texts, and continued to do so for at least the next twenty-five years. His work played an important role in reviving ancient mathematical skills and he also made significant contributions of his own. The five works we know of from this period are: the Liber abbaci (1202, 1228); the Practica geometriae (1220/1221); an undated letter to Theodorus, the imperial philosopher to the court of the Hohenstaufen emperor Frederick II; Flos (1225), a collection of solutions to problems posed in the presence of Frederick II; and the Liber quadratorum (1225), a number-theoretic book concerned with the simultaneous solution of equations quadratic in two or more variables. Fibonacci lived in the days before printing, so his books were hand written and the only way to have a copy of one of his books was to have another hand-written copy made, in light of this we are lucky to have such record as we do of his work.

Frederick II had summoned Fibonacci for an audience when he was in Pisa around 1225. His achievements were clearly recognised during his lifetime, although it was the practical applications rather than the abstract theorems that made him famous to his contemporaries.

After 1228 by decree the Republic of Pisa awarded Fibonacci a yearly stipend for his pro bono advising to the Republic on matters involving accounting and related mathematical matters. Fibonacci died some time after 1240.