The word algorithm sounds like modern tech jargon, but it is actually a centuries-old Latin rendering of one ninth-century scholar’s name. This deep dive follows al-Khwarizmi, a Persian-heritage mathematician who wrote in Arabic and worked as an astronomer and head of the library at the House of Wisdom in Baghdad under the Abbasid Caliph al-Mamun.

We explore how messy Islamic inheritance disputes pushed him to write al-Jabr, the book that gave us algebra, and why his shift from geometry to abstract operational logic mattered more than solving any single equation. Then we follow his work on Hindu-Arabic numerals and zero, his astronomical and trigonometric tables, and a 70-person project that redrew Ptolemy’s map of the world.

• How al-Jabr (restoration) and al-muqabala (balancing) turned inheritance math into a universal method written entirely in prose
• Why scholars still credit him over Diophantus and Brahmagupta: six standard equation forms and geometric proofs
• His text on Indian computation, the sand-covered dustboard, and how ‘Dixit Algorithmi’ became the word algorithm
• The Zij al-Sindhind astronomical tables and the sine and cosine values behind prayer times and navigation
• Using lunar eclipses as a global clock to shrink Ptolemy’s Mediterranean from 63 to 50 degrees of longitude