By Oula Mahfouz
From math to commerce to science and technology, numbers are indispensable tools in our daily lives. But where do these numbers originate throughout time and across civilizations?
The beginnings of numbers: Babylonians and Egyptians
The invention of number systems is attributed to the Babylonians around 2700 years before Christ. They developed the oldest known number system, the sexagesimal system, which calculates with 60 numbers and is still used today to represent time, angles, geographical coordinates and much more. Around 300 years later, the Egyptians developed their own method of counting, which is similar to today’s system. In the third century BC, the Indians introduced a number system comprising nine numbers.
Roman numerals – not really suitable for arithmetic
Roman numerals probably originated with the Etruscans around 500 to 600 B.C. They are made up of seven characters: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. These symbols evolved over time and were widely used in the Roman Empire and into the Middle Ages and early modern times. They did not prove to be very practical for mathematical calculations. Even today, however, they are still used for various purposes, for example for the hours on some clocks or for structuring official texts.
The introduction of Indian numerals in the Arabic world
The Arabs originally used letters to denote numbers. In 771, an Indian astronomer came to the court of the Abbasid caliph Abu Ja’far al-Mansur and brought with him a famous book on astronomy and mathematics, the Siddhanta of Brahmagupta, which was written in 628 and used these nine numerals. The Indians had several forms of numerals, and the Arabs selected a group of them, refined them and formed numerals that we now call Indian numerals or Eastern Arabic numerals. These were used by the Arabs in the Levant, especially in the capital Baghdad: ١ ٢ ٣ ٤ ٥ ٦ ٧ ٨ ٩.
Al-Khwarizmi imposes the decimal system and the zero
Al-Khwarizmi (ca. 780-850 AD) was an important mathematician and astronomer in the Golden Age of Islam. He played an important role in the popularization of the Indian number system in the Arab world. His work contributed to the spread of these numbers and the associated decimal system. Al-Khwarizmi is credited with designing the following Arabic numeral forms: 1, 2, 3, 4, 5, 6, 7, 8, 9.
There is a nice theory as to how the forms of the Arabic numerals came about: They are said to express the number of angles in each number. So 1 has one corner, 2 has two, 3 has three and so on, from 5 onwards the explanation becomes more complicated, as this video shows: https://youtu.be/emjXGNo9AJY?si=v6JgKIwAHDvPW6PV This theory can be found in Arabic sources, but its historical credibility is doubted by some scholars. Nevertheless, the theory contains a plausible and popular explanation.
In Al-Khwarizmi’s Arabic, zero is a number that only stands to the right of another number and has no value to the left of it. Al-Khwarizmi is also considered to be the first to establish algebra based on mathematical equations. The German word „Ziffer“, the English word „cipher“ and the French and English word „zero“ are all derived from the Arabic word „Ṣifr“, which means „empty“.
Al-Khwarizmi also developed the science of arithmetic and laid the foundations of algebra in his books. The concept of „algabr“ later became known as algebra. His contributions also extended to trigonometry and astronomy. The term „algorithm“ comes from a term describing his methods for solving mathematical problems and was derived from his name.
Al-Khwarizmi contributed to the spread of knowledge by translating Greek and Indian works into Arabic. His influence shaped the development of mathematics in the Golden Age of Islam.
Arabic numerals conquer Europe
Arabic numerals were initially not very popular in the Levant, but were well received by the Arabs in Andalusia and the Maghreb, from where they spread to Europe and then the rest of the world. Pope Sylvester II (946-1003), who studied at the University of Al-Qarawiyyin in Fez, Morocco, brought many Arabic sciences with him to Europe. He found it difficult to introduce Arabic numerals in Europe, where Latin/Roman numerals were widely used, as people believed in the superiority of Roman and Greek culture over all other cultures and did not accept the meaning of zero or Arabic numerals. Sylvester II therefore invented a new abacus table and used Arabic numerals on it.
Then the Italian mathematician Leonardo Fibonacci (1170-1250 AD) became acquainted with numbers in the city of Bejaia in Algeria. His work had a great influence on the adoption of numbers in Europe, and from there they spread to the rest of the world through trade, books and European colonialism. However, these numbers initially met with fierce resistance. In 1299, for example, the „counters“ in Florence succeeded in persuading the governors to pass a law banning the use of „new imaginary numbers“. With the invention of the printing press in the 15th century, Arabic numerals finally became established. In some places, however, Roman numerals were not replaced by Arabic numerals until the 18th century.
The development of our numerals is a story of cooperation between different cultures and the exchange of knowledge. Muslim scholars in the Golden Age of Islam contributed significantly to the development of mathematics. They laid the foundations for modern disciplines such as algebra, geometry and arithmetic. The Arabic numeral system they developed revolutionized mathematics. Important scholars such as Al-Khwarizmi, whose works were translated into Latin, and the Bayt al-Hikma „House of Wisdom“ knowledge center in Baghdad played a key role. Their achievements influenced not only the Islamic world, but also the entire world.
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Eine Wanduhr mit römischen Ziffern. Foto: tuenews INTERNATIONAL / Oula Mahfouz.
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