|Ab urbe condita||1840|
|Balinese saka calendar||1008–1009|
|English Regnal year||21 Will. 1 – 1 Will. 2|
|Chinese calendar||丙寅年 (Fire Tiger)|
3783 or 3723
— to —
丁卯年 (Fire Rabbit)
3784 or 3724
|- Vikram Samvat||1143–1144|
|- Shaka Samvat||1008–1009|
|- Kali Yuga||4187–4188|
|Japanese calendar||Ōtoku 4 / Kanji 1|
|Minguo calendar||825 before ROC|
|Seleucid era||1398/1399 AG|
|Thai solar calendar||1629–1630|
1213 or 832 or 60
— to —
1214 or 833 or 61
|Wikimedia Commons has media related to 1087.|
- Summer – The Taifa of Valencia falls under the domination of Rodrigo Díaz de Vivar (El Cid). He stabilizes the region around Valencia, which has revolted against the Moorish puppet ruler Al-Qadir.
- Inge the Elder returns to Svealand and kills his brother-in-law Blot-Sweyn after a 3-year reign. Inge again proclaims himself king of Sweden (approximate date).
- September 9 – King William I (the Conqueror) dies in Rouen after a fall from his horse. He is succeeded by his third son William II who becomes king of England.
- A fire in London destroys much of the city, including St. Paul's Cathedral. Bishop Maurice starts the rebuilding of a new, much larger cathedral.
- Mahdia campaign: The navies of Genoa and Pisa take the capital of the Zirids, and occupy Mahdia for a year. Subsequently, both republics obtain trading privileges.
- January 3 – Emperor Shirakawa abdicates in favor of his 7-year-old son Horikawa after a 14-year reign. He exerts his personal power to set the cloistered rule system further in motion.
- May 9 – The relics of Saint Nicholas, patron saint of seafarers, are stolen by Italian sailors from his church in Myra (modern Turkey) and transported to Bari in southern Italy.
- September 16 – Pope Victor III dies after a 1-year pontificate at Monte Cassino. He is buried in the abbey's chapter house.
- June 9 – Otto I (the Fair), prince of Olomouc (b. 1045)
- June 27 – Henry I (the Long), margrave of the Nordmark
- September 9 – William I (the Conqueror), king of England
- September 16 – Victor III, pope of the Catholic Church
- September 25 – Simon I, French nobleman (b. 1025)
- November 12 – William I, French nobleman (b. 1020)
- December 13 – Maria Dobroniega, duchess of Poland
- December 27 – Bertha of Savoy, Holy Roman Empress (b. 1051)
- Abu Bakr ibn Umar, military leader of the Almoravids
- Abū Ishāq Ibrāhīm al-Zarqālī, Arab astrologer (b. 1029)
- Arnold of Soissons (or Arnoul), French bishop (b. 1040)
- Asma bint Shihab, queen and co-regent of Yemen
- Blot-Sweyn, king of Svealand (approximate date)
- Eustace II, count of Boulogne (approximate date)
- Leo Diogenes, Byzantine co-emperor (b. 1069)
- Solomon (or Salomon), king of Hungary (b. 1053)
- Yaropolk Izyaslavich, prince of Turov and Volhyn
- Gilbert Meynier (2010). L'Algérie cœur du Maghreb classique. De l'ouverture islamo-arabe au repli (658-1518). Paris: La Découverte; p. 83.
- Gilbert Meynier (2010). L'Algérie cœur du Maghreb classique. De l'ouverture islamo-arabe au repli (658-1518). Paris: La Découverte; p. 56.
- Kleinhenz, Christopher (2010). Medieval Italy: an encyclopedia. New York: Routledge. p. 95. ISBN 0-415-93930-5.