Do You Know This Remarkable Andalusian Mathematician?

In today’s world, it’s almost impossible to think about mathematics without symbols. However, there was a time when these symbols did not exist. One of the key figures in this field who took significant steps in this direction was the Andalusian mathematician Abu Hasan ibn Ali al-Qalasadi.

Al-Qalasadi was born in 1412 in Baza, a small town near Granada. He studied Islamic sciences in his homeland until the age of 24. Over the next 15 years, he embarked on travels throughout North Africa and had the opportunity to meet with prominent scholars. Among them, the renowned hadith scholar Ibn Hajar al-Asqalani stands out, whom he met in Egypt. After these travels, he returned to Spain and settled in Granada, where he focused particularly on mathematics, law, and philosophy.

Al-Qalasadi is particularly renowned for his significant and influential works in the field of mathematics. He introduced new symbols to algebra and used a symbol for equality. For quadratic values such as x^2, he used the Arabic equivalent “m,” and for cubic values like x3, he used “k.” He standardized the use of terms like ‘ve’ for addition, ‘illa’ for subtraction, ‘fi’ for multiplication, and ‘ala’ for division. While it’s not certain, he is said to be the first person to separate the numerator and denominator in fractions with a line. He also emphasized the importance of the method of successive approximations, a crucial tool in calculations. All of these contributions serve as a key to understanding mathematics today. Al-Qalasadi’s interest in mathematics did not overshadow his artistic personality; he even wrote a book in which he explained algebraic rules through poetry. Additionally, it’s known that he authored books on grammar, jurisprudence, and hadith.

Unfortunately, al-Qalasadi’s story ends on a somber note. We consider him the last great mathematician of Andalusia, as just six years after his passing, Granada, Spain, became the last Muslim city to fall under Christian control. One year later, Archbishop Cisneros ordered the forced conversion of the remaining Jews and Muslims in the region and the burning of books, including the precious works of al-Qalasadi. Fortunately, his works and ideas survived and continued to be used for centuries.