Abū al-Ḥasan ibn ʿAlī al-Qalaṣādī (1412–1486)

Born 1412 CE, died 1486 CE.

Abu'l-Hasan Ali ibn Muhammad al-Qalasadi (Arabic: أبو الحسن علي بن محمد بن علي القرشي البسطي; 1412–1486) was a Muslim Arab mathematician from Al-Andalus specializing in Islamic inheritance jurisprudence. Franz Woepcke stated that al-Qalaṣādī was known as one of the most influential voices in algebraic notation for taking "the first steps toward the introduction of algebraic symbolism''. He wrote numerous books on arithmetic and algebra, including al-Tabsira fi'lm al-hisab (Arabic: التبصير في علم الحساب "Clarification of the science of arithmetic").

Text from the Wikipedia article Abu'l-Hasan_ibn_Ali_al-Qalasadi, licensed CC BY-SA 4.0.

Everything else in 1412 CE

HistoryLayer draws the world as it was in any year from 123,000 BCE to 2026. Move the slider and the borders redraw for that year; the map carries 23,890 events, 12,790 people, 837 wars and 13,183 cities, each one readable in place. Signing in is optional and lets you keep what you find.

HistoryLayer
1914CE
World Wars
123,000 BCE2026 CE
54 stops — one per surviving map on file, evenly spaced drag the pin · ←→ steps one stop the same 54 stops by true elapsed time ↑
Map & filters
Show on the map
Filter
Colour by
Polity Empire