|1140 by topic|
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|Births – Deaths|
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|Establishments – Disestablishments|
|Art and literature|
|1140 in poetry|
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- December 21 – Conrad III of Germany besieges Weinsberg, the stronghold of Welfs.
- Henry Jasomirgott is made count palatine of the Rhine.
- The town of Lanark in Scotland is made a Royal Burgh, by David I of Scotland.
- Marburg becomes a town.
- The Assizes of Ariano are enacted by Roger II of Sicily.
- Roger II of Sicily places the practice of medicine under royal control.
- August 21 – Jin–Song Wars: Battle of Yancheng – Song dynasty forces under the command of Yue Fei defeat a numerically superior Jin army led by Wuzhu.
- June 3 – Pierre Abelard is condemned for heresy by a church court in Sens, France.
- September 8 – Sephardi Jewish philosopher Judah Halevi, having completed the Kuzari, arrives in Alexandria on a pilgrimage to Palestine.
- The first Cistercian monastery in Spain is founded in Fitero. The order enjoys a rapid expansion in the region in the following 15 years.
- Camaldolite monk Gratian founds the science of Canon law with the publication of the Decretum Gratiani.
- May 28 – Xin Qiji, Chinese poet (d. 1207)
- Sophia of Minsk, queen consort of Denmark (d. 1198) (approximate date)
- Minamoto no Yoshihira, Japanese warrior (d. 1160)
- January 12 – Louis I, Landgrave of Thuringia
- February 6 – Thurstan, Archbishop of York
- February 14
- September 15 – Adelaide of Hungary, Duchess of Bohemia
- date unknown – Kitti Sri Megha, King of Dakkinadesa, Sri Lankan