Fibonacci's Liber Abaci
Hindu–Arabic numerals begin to replace Roman ones
In 1202 Leonardo of Pisa, known as Fibonacci, published Liber Abaci, introducing Europeans to Hindu–Arabic numerals and positional notation. Merchants soon saw how much easier calculation became.
Wikipedia (Russian) · Wikipedia (English) · 13th century
Meanwhile around the world (±25 years)
Eastern Europe & Russia
- 1185 Prince Igor's campaign — 17 years earlier
- 1223 Battle of the Kalka River — 21 years later
Asia
- 1192–1333 First shogunate in Japan — 10 years earlier
- 1206 Temüjin proclaimed Genghis Khan — 4 years later
- 1206 Founding of the Delhi Sultanate — 4 years later
Alive at the time
- Genghis Khan (aged 40)
- Vsevolod the Big Nest (aged 48)
- Philip II Augustus (aged 37)
- John Lackland (aged 36)
- Francis of Assisi (aged 20)
- Frederick II (aged 8)
- Jayavarman VII (aged 80)
- Eleanor of Aquitaine (aged 78)
- Maimonides (aged 64)
- Tamar of Georgia (aged 36)