History knows many talented mathematicians that made a notable contribution to the further development of science. One of them is the legendary mathematician of medieval Europe, Leonardo Fibonacci. His biography explains how Leonardo Fibonacci managed to develop his theories that brought mathematics to the new level of its development.
Leonardo Fibonacci was a famous Italian mathematician. Despite his fame in the modern world, only brief biographical facts are known about his life. His birth name was Pisano, but he took the nickname Fibonacci, which means the son of Bonacci. It is known that he was born in Italy, in the family of Bonacci in Pisa in around 1175, and died after 1240 (Swetz, 2013). His father was a merchant and consul for Pisa. He often went on business to the Bug (present-day Algeria) and took Leonardo with him (Swetz, 2013).
Thanks to these travels to the East, Leonardo studied mathematics from Arab teachers (Swetz, 2013). In Bugia, Fibonacci examined a new number system, which was used by the locals (Omotehinwa & Ramon, 2013). He was so fascinated by the art of counting with the help of nine Hindu signs that he went on travel to other Mediterranean countries for studying more about mathematics. Having traveled all these countries, Fibonacci became convinced that the Hindu system of figures 1, 2, 3, 4, 5, 6, 7, 8, 9 and 0, was the most proficient number system (Omotehinwa & Ramon, 2013). In Europe, at that time, the Roman system for counting was used, which was far not easy. Leonardo believed that the Indian system of figures had huge advantages in comparison with the Roman system and hoped that the peoples of Europe should accept it (Omotehinwa & Ramon, 2013).
After having studied this system and everything that was relevant to it thoroughly and developed his own thoughts and research, Fibonacci returned to Pisa and began writing his first work, Liber Abaci (Swetz, 2013). This book was finished in 1202 and was geared towards not only scientists but also a wide range of readers (Swetz, 2013). Liber Abaci (1202) became a true encyclopedia of arithmetic and algebraic knowledge (Omotehinwa & Ramon, 2013). In particular, with the help of this book, the Europeans learned about the Hindu-Arabic figures.
In his outstanding book, Liber Abaci (1202), Leonardo Fibonacci presented a significant part of the knowledge he had learned during his travels. He considered a wide range of topics and concepts, including the new Hindu numbering system, fractions, subtraction, addition, multiplication, divisibility, ways of calculating square and cubic roots, arithmetic and geometric progressions, algebra, proportions, and linear equations. Several chapters of the book analyzed calculating profits and interest payments, currency conversions. It means that the book was of great interest to European trade and business. As a result, Liber Abaci had a greater impact on the commercial world than on the scientific world (Swetz, 2013).
The important value of Liber Abaci (1202) was explained by the presence of numerous diverse tasks in it. One of the most famous ones considered the reproduction of rabbits. His observations led Fibonacci to the discovery of the numerical sequence 1, 1, 2, 3, 5, 8, 13, …, in which each number was equal to the sum of the previous two. It also showed a very interesting feature a constant relationship between numbers (Scott & Marketos, 2014). This numerical sequence was subsequently called the Fibonacci sequence. Having discovered the famous sequence of numbers, Fibonacci completely changed the human outlook on the surrounding world and the laws of its existence. The following sequence can be found in nature, art, architecture, music, and biology (Omotehinwa & Ramon, 2013).
In 1220, Fibonacci wrote his second book, The Practice of Geometry, which contained eight chapters on various theorems (Scott & Marketos, 2014). This year, his first work attracted the attention of the emperor of the Roman Empire, Frederick II (Swetz, 2013). Leonardo was invited to the imperial court and was asked to do a number of mathematical questions, to which other mathematicians could not find answers. He published his solutions to these problems in the treatise, The Flower, in 1225 (Omotehinwa & Ramon, 2013). Since then, the correspondence of Frederick II with the scientist had lasted for several years. The two discussed various mathematical problems. Fibonacci devoted the next book, Liber Quadratorum, (1225) to the Roman emperor. It contained a number of problems to solve uncertain quadratic equations (Swetz, 2013).
It is difficult to overestimate the contribution of Leonardo Fibonacci to the development of mathematics and the popularization of mathematics in Europe. The book Liber Abaci (1202) was widely distributed and was one of the most important books on mathematics in the Middle Ages. Nevertheless, his most creative work is the book, Liber Quadratorum (1225), which is considered a true masterpiece. Thanks to it, Fibonacci received the title of the main contributor to the theory of numbers (Swetz, 2013). Thus, the mathematical discoveries of Leonardo Fibonacci were of great importance and were widely used in various fields of science.
It is possible to assert that Leonardo Fibonacci was one of the first major mathematicians of medieval Europe. Fibonacci is a legendary figure in mathematics, economics, and finance. He wrote a number of mathematical tracts, including Liber Abaci (1202), Liber Quadratorum (1225), The Practice of Geometry (1220), and Flower (1225). His work was an outstanding phenomenon of the medieval science of Western Europe. By introducing the Arabic numerals, he significantly changed medieval mathematics and brought it to a new level. Thus, his contribution to science is inestimable. The sequence of numbers discovered by Fibonacci has been used in mathematics for centuries. Many generations of scientists have grown up on his books and theorems. For this reason, the development of science and the European civilization as a whole was defined by Leonardo Fibonacci to a great extent.