Leonardo Fibonacci
Who Brought Europe The Nine Figures · Mathematician & Merchant's Son · c. 1170 – c. 1245
The Pisan who learned reckoning in North Africa and wrote the book that taught Latin Europe to calculate with the nine figures and the zero.
Who was Fibonacci?
Leonardo of Pisa was the son of Guglielmo, a Pisan customs official posted to Bugia on the North African coast, and it was there that his father arranged for him to be taught calculation by a Muslim master. He then travelled the Mediterranean — Egypt, Syria, Byzantium, Sicily, Provence — comparing the methods of reckoning in use in each place, and concluded that none approached the Indian one. In 1202 he published the Liber Abaci, the Book of Calculation. Its opening pages introduce Latin Europe to the nine figures and the sign zephirum, with which any number whatever can be written, and the remaining several hundred are a working handbook for merchants: currency exchange between cities using different coinages, barter, the division of profit among partners, weights and measures that change at every port, the rule of three, and the extraction of roots. Fractions he writes with a bar, frequently as a sum of parts with one on top, and placed to the left of the whole number rather than the right. One problem among hundreds asks how many pairs of rabbits there will be after a year if each pair breeds according to a stated rule; the sequence it generates was named after him by the French mathematician Édouard Lucas in the nineteenth century, six hundred years after his death, and had already been described by Indian scholars of poetic metre well before he was born. In 1240 the Republic of Pisa granted him a salary in recognition of his services in accounting and instruction. Europe's merchants adopted his figures long before its universities did.
Major achievements
- Published the Liber Abaci in 1202, the book that carried the Hindu-Arabic numerals into Latin Europe
- Set out place value and the sign for zero for a Western readership
- Wrote a complete working handbook of commercial arithmetic — exchange, barter, profit division, the rule of three
- Introduced the fraction bar to European practice
- Wrote the Practica Geometriae and the Liber Quadratorum, the latter a genuine work of number theory
Life in brief
- c. 1170 — Born: At Pisa, into a family of merchants and officials.
- c. 1185 — Bugia: Taught calculation in North Africa, where his father was posted.
- c. 1190s — Travels: Egypt, Syria, Byzantium, Sicily and Provence, comparing methods of reckoning.
- 1202 — Liber Abaci: The nine figures, the zephirum, and several hundred pages of merchants' problems.
- 1220 — Practica Geometriae: A treatise on measurement and geometry for surveyors.
- 1225 — Liber Quadratorum: His most original work, on square numbers — and the court of Frederick II.
- 1240 — A salary from Pisa: Granted in recognition of his services in accounting and teaching.
- c. 1245 — Died: At Pisa; the figures he taught took three centuries more to win.
Explore the life of Fibonacci — five chapters
- The Boy at Bugia — Sent abroad, and shown a better way to count
- The Book of Calculation — Nine figures, one sign for nothing, and several hundred problems about money
- The Rabbits — One problem among hundreds, and the only one anybody remembers
- Three Centuries of Resistance — Why the better system took so long to win
- A Salary from the Republic — The court of the Emperor, and what was left behind
Read the five-chapter life of Leonardo Fibonacci →
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- Explore the life of Fibonacci — five chapters
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