Diophantus writes the Arithmetica
The unknown in an equation gets its own symbol
The Alexandrian mathematician Diophantus wrote the Arithmetica, thirteen books of problems solved in rational numbers, in which the unknown and its powers first got symbols of their own. In the margin of its Latin translation Pierre de Fermat jotted down his 'last theorem'.
Wikipedia (Russian) · Wikipedia (English) · 3rd century
Meanwhile around the world (±25 years)
Europe
- 235–284 The Crisis of the Third Century begins — 15 years earlier
- 260–274 Postumus founds the Gallic Empire — 10 years later
Middle East
- c. 240 Mani begins to preach — 10 years earlier
- 260 Battle of Edessa: a Roman emperor taken captive — 10 years later
Americas
- c. 250 Rise of the Classic Maya cities — same year
Oceania
- c. 232 Hatepe eruption of Taupō — 18 years earlier