In the era of the Abbasid Caliph al-Ma’mun (d. 218 AH/833 AD), Islamic civilization opened up to the rest of the neighboring civilizations when this caliph established the famous “House of Wisdom” institution, which was the most recent research and scientific institution at the time, in which empirical and mental sciences were taken, such as mathematics, medicine, chemistry, pharmacy, drugs and even philosophy and history. Byzantine position of translation and transmission.
Research in mathematics has expanded, especially in algebra at the hands of Arabs and Muslims, and in this regard, Gustave Le Bon, the famous French philosopher and historian says:
And Gustave Le Bon, in his brilliant book “The Civilization of the Arabs,” quotes the French scientist Monsieur Chall in his book “A Summary of the History of the Origins of Geometry” as saying that “the blessed (Arab-Islamic) scientific revolution that led to the introduction of those heavy complex methods in the pocket and in the pocket did not affect scholars.” modern centuries until after the lapse of five hundred years, at the invitation of Reggio Montanos, although the Copernican revolution that appeared after nearly a century was ignorant of that revolution”[2]! In fact, the scientific revolution brought about by Muslims in the east and west of the Islamic world had its resounding impact and resonance in Europe, especially during the Crusades and their aftermath in the eleventh, twelfth and thirteenth centuries AD and what followed, thanks to the expansion of trade between the northern Mediterranean, especially in Italy, Spain and its south. In Egypt, the Levant, Algeria and Morocco.
And during those political, scientific, economic and military interactions, Leonardo Fibonacci Al-Bissi was born to hide from fate a surprise that will change the history of scientific relations between Islam and the West, and mathematics takes a revolutionary turn in world history to this day. Who is Fibonacci? Where was he born? How did the Arabic numerals transfer from Islamic geography to the Holy Roman Empire during the twelfth century AD? What is the impact of this on Europe and the world? That is what we will see in our next lines.
In the city of Pisa, one of the metropolises of the Italian region of Tuscany near the Mediterranean Sea, and in the year 1180 AD / 576 AH, Leonardo was born in that city, which was teeming with a mixture of Italian nations, Turks, Libyans, Persians and Arabs, and the small fishing port of the city had gained from his struggle with Muslims during the Crusades Especially in Sardinia and Sicily, a strategic center and a huge wealth. This city became the link between East and West trade. Through diplomatic and commercial means, it was able to set up commercial hotels in the most important cities of the Mediterranean and its coasts from Constantinople and Alexandria to Bejaia in Algeria and Ceuta in Morocco.
Hence, Leonardo’s father worked as head of the commercial center of Pisa in the city of Bejaia on the southern Mediterranean coast of Algeria, and Anna Marie Schimmel tells us in her fair book “The Sun of Arabs Shines on the West” that “everything Leonardo mentioned in his books is the name of his father “Bonaccio”, meaning The good, and Leonardo later introduced himself as “Leonardus Filis Bonacci” (meaning Leonardo’s son of the good), then Leonardo was later known by the name by which historians know him “Leonardus Fibonacci” [3].
Leonardo lived his childhood years with his father in the city of Bejaia, and compared to his years of birth and childhood, we will notice that he lived in the golden age of the Almohads in North Africa and Andalusia in the last quarter of the sixth century AH, at the height of the conflict of the Crusades, and it was natural to prepare the Byzantine merchant his son Leonardo To be a merchant like him, he would teach him the principles of arithmetic and mathematics, and handed him over to an Arab teacher who would teach him this skill. Leonardo was fond of Arabic numerals, and he was intelligent and loving this science, and soon he learned multiplication and division and mastered them, and his teacher “Sidi Omar” taught him to calculate fractions on the latest methods. Which was taught in the prestigious universities in Baghdad, Cairo and Mosul at the time, and also learned the roots and the solution of mathematical equations that Muslims had reached in the books of Ibn Sina, Al-Biruni, Al-Khwarizmi and others[4].
Leonardo toured the Islamic countries in the East and the Maghreb, in Ceuta, Tunisia, Alexandria, Cairo and Damascus, and studied everything contained in the manuscripts of the great mathematicians from the Greeks, Indians and Arabs. At the age of twenty-three, Leonardo wrote his famous book “Liber Abaci”[5] in 1202AD. The Counting Book” or “Abacus” in Latin became a revolution in the history of arithmetic and mathematics in the European continent in the thirteenth century AD
In this book we saw the first complete European presentation of the Indo-Arabic numerals, the zero, and the decimal method, by a Christian author, and it was, as Will Durant says in The Story of Civilization, “the beginning of the revival of mathematical sciences in the countries of Christian Europe. This same book introduced Arabic algebra In Western Europe, he brought about a simple revolution in that science because he used from time to time letters instead of numbers to generalize and reduce algebraic equations.Leonardo used in his book “Practica geometrica” (1220)) for the first time in the Christian world on what we know algebra in He solved geometric theorems, and in two other books published in 1225, he put innovative ways to solve equations of the first and second degree. In that same year, Frederick II headed a mathematical festival in Pisa, in which John Palermo put different problems solved by Fibonacci “[6].
But one of the funny and strange things that spread in Europe at that time was the resistance to everything new, even if it facilitated the people of this continent. “Europe’s merchants continued to resist the new method of counting despite the appearance of this author, which is the beginning of a new era in the history of mathematical sciences. Many were Some of them prefer to move the counter with their fingers and write the results in Roman numerals, and in 1299 the “enumerators” in Florence were able to convince the rulers to enact a law forbidding the use of “new imaginary numbers”, and only a few mathematicians realized that the new symbols, which are zero and the order of the decimal places in The ones, tens and hundreds, have paved the way for the development of mathematical sciences, a development that would be almost impossible if they continued to take the ancient Greek, Roman and Jewish letters as numbers. The Indian numerals did not eventually replace the Roman numerals until the sixteenth century”[7].
As soon as the benefit of using Arabic numerals became clear to the minds, people adopted them for most of their scientific purposes. By adopting these numbers, several Arabic words entered the European languages. The French word “Chiffre”, the German “Ziffer”, the English “Cipher”, as well as the French and English “Zero” They are all derived from the Arabic word “zero” meaning “empty.” The invention of this sign came late, and it caused a revolution, as Montgomery Watt says in “The Virtue of Islam over Western Civilization” [8].
Leonardo wrote in the first chapter of his book “Liber Abaci” about the Arabic numerals saying: “The nine Indian numerals are: 1, 2, 3, 4, 5, 6, 7, 8, 9. By them all, besides that sign.” 0, which is called the Arabic zero, any number whatsoever can be written. And Leonardo – as the great German orientalist Anna Marie Schimmel says – “reads like Arabs from right to left, and even fractions are written to the left of whole numbers, so he writes, for example: one and a half on this picture 1/2, and as his Arab teacher taught him when he was a boy, Leonardo began In the education of the West these numbers, including that sign “0”, which the Arabs call zero” [9].
It is important to say that when Fibonacci transferred the Indo-Arabic numerals with the latest developments in algebra and its equations to the European continent, which some of them received in his time with great enthusiasm and a hostile majority, he also transmitted to them what was known as the “Fibonacci sequence”, and the Fibonacci sequence or Fibonacci numbers in mathematics are the numbers that It is in the following sequence: 1-2-3-5-8-13-21-34-55-89… that is, we add each number to the number that precedes it, and so on, and each number is the product of the sum of the two preceding numbers.
Among the most important applications of this series is the so-called golden ratio, which we find in nature in a large way, in flowers, in the world of living organisms, in the human body, and many forms in nature. Indeed, this arithmetic sequence is used today in digital data, trading in global stock markets, and others, And all this was thanks to Fibonacci’s learning of mathematics and Arabic algebra, those sciences that collected the summary of Indian and Greek mathematics and added to it the innovations of Arabs and Muslims and their new developments in these fields, especially “zero” which revolutionized the history of geometry, calculations and numbers to this day.