Sacrobosco's De sphaera
A medieval textbook on the round Earth, in use for 400 years
Around 1230 the Paris master John of Sacrobosco wrote an astronomy textbook arguing that the Earth is a sphere. It was read in every European university for about 400 years and reprinted dozens of times after printing arrived.
Wikipedia (English) · 13th century
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Medieval scholars knew the Earth was round. Sacrobosco's textbook On the Sphere, written around 1230, was standard reading in European universities for some 400 years. Share →
Meanwhile around the world (±25 years)
Eastern Europe & Russia
- 1223 Battle of the Kalka River — 7 years earlier
- 1237–1240 Mongol invasion of Rus' — 7 years later
- 1240 Batu Khan takes Kiev — 10 years later
- c. 1242 The Golden Horde is founded — 12 years later
Asia
- 1206 Temüjin proclaimed Genghis Khan — 24 years earlier
- 1206 Founding of the Delhi Sultanate — 24 years earlier
- 1219 The Mongols invade Khwarazm — 11 years earlier
- c. 1251 The Tripitaka Koreana — 21 years later
Oceania
- c. 1250 The moai of Easter Island — 20 years later
Alive at the time
- Kublai Khan (aged 15)
- Alexander Nevsky (aged 9)
- Frederick II (aged 36)
- Rumi (aged 23)
- Saint Louis (Louis IX) (aged 16)
- Sundiata Keita (aged 13)
- Rudolf I (aged 12)
- Thomas Aquinas (aged 5)
- Fibonacci (aged 60)
- Yuri II of Vladimir (aged 41)