Year 1158 (MCLVIII) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar.
|Ab urbe condita||1911|
|Balinese saka calendar||1079–1080|
|English Regnal year||4 Hen. 2 – 5 Hen. 2|
|Chinese calendar||丁丑年 (Fire Ox)|
3854 or 3794
— to —
戊寅年 (Earth Tiger)
3855 or 3795
|- Vikram Samvat||1214–1215|
|- Shaka Samvat||1079–1080|
|- Kali Yuga||4258–4259|
|Japanese calendar||Hōgen 3|
|Minguo calendar||754 before ROC|
|Seleucid era||1469/1470 AG|
|Thai solar calendar||1700–1701|
1284 or 903 or 131
— to —
1285 or 904 or 132
- Autumn – Emperor Manuel I (Komnenos) sets out from Constantinople at the head of an expeditionary army. He marches to Cillicia; and while the main army follows the coast road eastwards – Manuel hurries ahead with a force of only 500 cavalry. He manages to surprise King Thoros II (the Great), who has participated in the attack on Cyprus (see 1156). Thoros flees into the mountains and Cilicia is occupied by the Byzantines.
- January 11 – Vladislav II becomes king of Bohemia. He is crowned by Emperor Frederick I (Barbarossa) with a diadem (called by the chroniclers a diadema or circulus). Vladislaus is also invested with Upper Lusatia, and accompanies Frederick to Milan to suppress the rebellion in Lombardy (Northern Italy).
- The Diet of Roncaglia is convoked by Frederick I. He mobilises an army of 100,000 men and leaves in June for a second Italian expedition – accompanied by Henry the Lion and his Saxon forces. He crosses the Alps and lays siege to Milan. German forces capture the city from the rebels after a short siege. However Milan soon rebels again, with Empress Beatrice taken captive and forced into parading on a donkey.
- Raymond of Fitero, Spanish monk and abbot, pledges to defend the fortress of Calatrava (guarding the roads to Córdoba and Toledo) from incoming Muslim raiders. It is the founding moment of the Order of Calatrava, the spearhead of the Iberian armies during the Reconquista.
- August 31 – King Sancho III (the Desired) dies after a 1-year reign. He is succeeded by his 2-year-old son Alfonso VIII (the Noble) as ruler of Castile. The noble houses of Lara and Castro claim the regency, as the boy's uncle, Ferdinand II (ruler of León and Galicia).
- Portuguese forces, led by King Afonso I (the Great), conquer Pamela, Alcácer do Sal and Sesimbra from the diminished Almoravids.
- Summer – King Henry II travels to France to meet King Louis VII and propose a marriage between his three-year-old son Henry and Louis' daughter Margaret (less than a year old). She is shipped to England, as the future wife and queen. The Vexin region is promised to Margaret as dowry and is put under the care of the Knights Templar, until her future husband is old enough to take control of it.
- The 12-year-old William Marshal is sent to the Château de Tancarville in Normandy to be brought up in the household of William the Tancarville, a cousin of William's mother. He begins his training as a knight, this also includes academic studies, practical lessons in chivalry and courtly life, and warfare and combat (using wooden swords and spears).
- Welsh forces under Ifor Bach (Ivor the Short) attack Cardiff Castle and kidnap William Fitz Robert, Norman lord of Glamorgan, along with his family.
- September 5 – Emperor Go-Shirakawa abdicates the throne after a 3-year reign. He is succeeded by his 15-year-old son Nijō as the 77th emperor of Japan. Go-Shirakawa retains power, and gives Kiyomori Taira a higher position to lead a samurai-dominated government.
- The English Pound Sterling (currency) is introduced.
- The University of Bologna is granted its first privileges by Frederick I.
- The Diocese of Derry is founded in Ireland.
- August 6 – Al-Nasir li-Din Allah, Abbasid caliph (d. 1225)
- September 23 – Geoffrey II, duke of Brittany (d. 1186)
- Albert I (the Proud), margrave of Meissen (d. 1195)
- Baldwin of Bethune, French nobleman (d. 1212)
- Ermengol VIII (or Armengol), count of Urgell (d. 1208)
- Fujiwara no Ietaka, Japanese (waka) poet (d. 1237)
- Giordano Forzatè, Italian religious leader (d. 1248)
- Henry I, French nobleman and knight (d. 1190)
- Henry I (the Elder), German nobleman (d. 1223)
- Jinul (or Chinul), Korean Zen Master (d. 1210)
- Margaret of France, daughter of Louis VII (d. 1197)
- Philip of Dreux, bishop of Beauvais (d. 1217)
- Satō Tsugunobu, Japanese warrior (d. 1185)
- Taira no Shigehira, Japanese general (d. 1185)
- Theobald I, French nobleman and knight (d. 1214)
- Valdemar Knudsen, Danish bishop (d. 1236)
- Yvette of Huy, Belgian anchoress (d. 1228)
- April 26 – Martirius, archbishop of Esztergom
- July 19 – Wibald, German monk and abbot (b. 1098)
- July 27 – Geoffrey VI, count of Nantes (b. 1134)
- August 20 – Rögnvald Kali Kolsson, Earl of Orkney
- August 31 – Sancho III, king of Castile (b. 1134)
- September 22 – Otto I, German bishop (b. 1114)
- December 15 – Frederick II, German archbishop
- Abu Jafar ibn Atiyya, Almohad vizier and writer
- Anselm of Havelberg, German bishop (b. 1100)
- Barthélemy de Jur, French bishop (b. 1080)
- Oda of Brabant, Belgian prioress and saint
- Thorbjorn Thorsteinsson, Norwegian pirate
- ^ Runciman, Steven (1952). A History of The Crusades. Vol II: The Kingdom of Jerusalem, p. 286. ISBN 978-0-241-29876-3.
- ^ Comyn, Robert (1851). History of the Western Empire, from its Restoration by Charlemagne to the Accession of Charles V, p. 236–38.
- ^ Estow, Clara (1982). "The Economic Development of the Order of Calatrava, 1158–1366". Speculum. 57 (2): 267–291. doi:10.2307/2847457. JSTOR 2847457. S2CID 164086223.
- ^ Picard, Christophe (2000). Le Portugal musulman (VIIIe-XIIIe siècle. L'Occident d'al-Andalus sous domination islamique. Paris: Maisonneuve & Larose. p. 110. ISBN 2-7068-1398-9.
- ^ King John by Warren. Published by University of California Press in 1961. p. 27.