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Person: Al Qalasadi, Abu&amp;#x27;l Hasan ibn Ali
Al-Qalasadi was a Spanish Islamic mathematician who took the first steps toward the introduction of algebraic symbolism by using letters in place of numbers.
Mathematical Profile (Excerpt):
- The Christian kingdom of Castile to the north had suffered civil strife through the 14th Century, so Andalusia had prospered but, in 1407, five years before al-Qalasadi was born, Castile began a major push to conquer the whole of Spain and Portugal.
- Al-Qalasadi was a Muslim who was brought up in Bastah which is north-east of Granada city.
- Al-Qalasadi began his education in Bastah, studying law, the Qur'an and the science of fixed shares in an estate.
- Al-Qalasadi chose to remain in the Islamic world and he left Granada and travelled widely throughout Islamic territory.
- Form there al-Qalasadi went to Egypt where again he studied with some of the leading scholars.
- Eventually al-Qalasadi reached Mecca, the purpose of his pilgrimage, and returned to Granada.
- Things were in a bad way when al-Qalasadi returned to Granada.
- However, al-Qalasadi taught and wrote some of his major works during this period but eventually the advancing Christian armies made life impossible for him.
- The defeat of the whole Muslim state in Granada finally took place until 1492, six years after al-Qalasadi's death in North Africa, when the city of Granada fell to Christian Castile.
- Ibn al-Banna was a Moroccan who had died over 100 years before al-Qalasadi wrote his commentary but, perhaps surprisingly, ibn al-Banna himself had written a commentary on his own work.
- Certainly al-Qalasadi wrote original works.
- This was a difficult text and, perhaps to some extent following the example of ibn al-Banna, al-Qalasadi followed it up by writing a simpler version which he called Unveiling the science of arithmetic.
- Both of the simpler versions of al-Qalasadi's arithmetic treatise proved popular in teaching arithmetic in North Africa and the works were in use for over 100 years.
- It is now certain that, despite being popular teaching books, there was little original in al-Qalasadi's work.
- The difficulty was that al-Qalasadi, being one of the last of the mathematicians associated with the major mathematical contributions by the Muslims and Arabs, was better known than many of the earlier contributors.
- Ignorance of the earlier contributions led historians to give too much credit to al-Qalasadi whom in many ways displayed the same characteristics as the later ancient Greek mathematicians.
- This leads him to stress the importance of the algebraic symbolism used by al-Qalasadi (1412-1486) without taking into consideration similar previous attempts both in Eastern and in Western Islam, a fact which was already known - in the second half of the 19th century - by F Woepcke.
- 1321, a Moroccan) and al-Qalasadi (d.
- Certainly symbols were not the invention of al-Qalasadi.
- We should not, however, let any of this argument detract from al-Qalasadi's contribution.
Born 1412, Bastah (now Baza, Spain). Died 1486, Béja, Tunisia.
View full biography at MacTutor
Tags relevant for this person:
Ancient Arab, Origin Spain
Thank you to the contributors under CC BY-SA 4.0!
Adapted from other CC BY-SA 4.0 Sources:
- O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive