|Ab urbe condita||1843|
|Balinese saka calendar||1011–1012|
|English Regnal year||3 Will. 2 – 4 Will. 2|
|Chinese calendar||己巳年 (Earth Snake)|
3786 or 3726
— to —
庚午年 (Metal Horse)
3787 or 3727
|- Vikram Samvat||1146–1147|
|- Shaka Samvat||1011–1012|
|- Kali Yuga||4190–4191|
|Japanese calendar||Kanji 4|
|Minguo calendar||822 before ROC|
|Seleucid era||1401/1402 AG|
|Thai solar calendar||1632–1633|
1216 or 835 or 63
— to —
1217 or 836 or 64
|Wikimedia Commons has media related to 1090.|
- A third Almoravid expedition is launched in Al-Andalus, designed to finally subdue the Taifa's Kingdoms. The cities of Córdoba, Seville, Granada, Málaga, Almería and Ronda fall to the troops of Sultan Yusuf ibn Tashfin.
- King Stephen II of Croatia becomes involved in an open conflict between factions of Croatian nobles, who reassert their traditional rights in their own counties.
- Hassan-i Sabbah founds the Nizari Ismaili state after taking control of the Alamut Castle and organising the military group called the Order of Assassins.
- Béjaïa (or Bugia) becomes the capital of the Hammadid Dynasty in modern Algeria. It becomes an important port and centre of culture.
Arts and CultureEdit
- Troubadours begin playing in western Aquitaine (Poitou and Saintonge) and Gascony (approximate date).
Science and TechnologyEdit
- January 17 – Qin Hui, Chinese chancellor and traitor (d. 1155)
- unknown dates
- Fujiwara no Atsuyori (or Dōin), Japanese waka poet (d. 1179)
- Agnes I, German abbess of Quedlinburg (approximate date)
- Alaungsithu, Burmese king of the Pagan Dynasty (d. 1167)
- Arnold of Brescia, Italian canon regular (approximate date)
- Bernard of Clairvaux, French abbot and theologian (d. 1153)
- Chen Yuyi, Chinese politician of the Song Dynasty (d. 1138)
- Eliezer ben Nathan, German rabbi and liturgical poet (d. 1170)
- Eric II (the Memorable), king of Denmark (approximate date)
- Fujiwara no Akisuke, Japanese nobleman and poet (d. 1155)
- Juliane de Fontevrault, illegitimate daughter of King Henry I of England
- Conrad I, German nobleman and rector of Burgundy (d. 1152)
- Niklot (or Nyklot), Obotrite prince and tribal chief (d. 1160)
- Robert FitzRoy, 1st Earl of Gloucester
- Theobald II (the Great), French nobleman
- Theobald of Bec, archbishop of Canterbury
- William de Mohun, 1st Earl of Somerset
- March 22 – García II, king of Galicia and Portugal (b. 1042)
- April 16 – Sikelgaita, Lombard duchess of Apulia (b. 1040)
- May 3 – Adelaide of Rheinfelden, queen consort of Hungary
- May 12 – Liutold of Eppenstein, German nobleman
- May 18 – Berthold of Rheinfelden, German nobleman
- June 26 – Jaromír, Bohemian prince and bishop
- July 3 – Egbert II (or Ekbert), German nobleman
- August 11 – Fujiwara no Atsuie, Japanese nobleman (b. 1033)
- August 13 – Constance of Normandy, duchess of Brittany
- unknown dates
- Gilbert Meynier (2010). L'Algérie cœur du Maghreb classique. De l'ouverture islamo-arabe au repli (658-1518). Paris: La Découverte; p. 83.
- Steven Runciman (1952). A History of the Crusades. Vol II: The Kingdom of Jerusalem, pp. 96–97. ISBN 978-0-241-29876-3.
- John B. Freed (January 1, 2016). Frederick Barbarossa: The Prince and the Myth. Yale University Press. p. 19. ISBN 978-0-300-12276-3.
- McMillan, Peter. 2010 (1st ed. 2008). One Hundred Poets, One Poem Each. New York: Columbia University Press. Page 146
- Eleventh-century Germany: The Swabian chronicles. Manchester University Press. January 1, 2013. p. 299. ISBN 978-1-5261-1282-8.
- Kanō, higefumi (1983). "Fujiwara no Atsuie" 藤原敦家. Nihon Koten Bungaku Daijiten 日本古典文学大辞典 (in Japanese). 5. Tokyo: Iwanami Shoten. p. 267. OCLC 11917421.
- Barnhart, R. M. et al. (1997). Three thousand years of Chinese painting. New Haven, Yale University Press. ISBN 0-300-07013-6 Page 372
- Alban Butler; Paul Burns (January 1, 1997). Butler's Lives of the Saints. A&C Black. p. 84. ISBN 978-0-86012-254-8.