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Thinkers Timeline

Key thinkers across history — grouped by era, colour-coded by discipline. Click any card to explore ideas, quotations, and classroom contexts.

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Medieval — 500 to 1500
Al-Khwārizmī c. 780-c. 850 · Persia / Abbasid Caliphate (active in Baghdad)
Muḥammad ibn Mūsā al-Khwārizmī was a Persian scholar born around 780, probably in Khwarezm, a region in what is now Uzbekistan. His family name, al-Khwārizmī, means 'from Khwarezm'. He spent most of his working life in Baghdad, the capital of the Abbasid Caliphate. Baghdad at that time was one of the world's great centres of learning. He worked at the House of Wisdom, a famous library and research centre set up by the Caliph al-Ma'mūn. Scholars there translated Greek, Persian, and Indian texts into Arabic and wrote original works of their own. Al-Khwārizmī was one of the most important scholars of his generation. He wrote on mathematics, astronomy, geography, and the calendar. His most famous book is usually called al-Kitāb al-mukhtaṣar fī ḥisāb al-jabr wa'l-muqābala, or The Compendious Book on Calculation by Completion and Balancing. The word al-jabr in the title gave us the English word algebra. Another of his books explained how to calculate using the Hindu numerals from India. This book, translated into Latin centuries later, spread these numerals across Europe. We call them Arabic numerals today, but they came from India through scholars like him. He died around 850. Many of his works survive. Some exist only in later Latin translations. His influence on mathematics is hard to overstate.
"That fondness for science, by which God has distinguished the Imām al-Ma'mūn... has encouraged me to compose a short work on Calculating by Completion and Reduction."