|Ab urbe condita||1876|
|Balinese saka calendar||1044–1045|
|English Regnal year||23 Hen. 1 – 24 Hen. 1|
|Chinese calendar||壬寅年 (Water Tiger)|
3819 or 3759
— to —
癸卯年 (Water Rabbit)
3820 or 3760
|- Vikram Samvat||1179–1180|
|- Shaka Samvat||1044–1045|
|- Kali Yuga||4223–4224|
|Japanese calendar||Hōan 4|
|Minguo calendar||789 before ROC|
|Seleucid era||1434/1435 AG|
|Thai solar calendar||1665–1666|
1249 or 868 or 96
— to —
1250 or 869 or 97
|Wikimedia Commons has media related to 1123.|
- April 18 – King Baldwin II of Jerusalem is captured by Turkish forces under Belek Ghazi – while preparing to practice falconry near Gargar on the Euphrates. Most of the Crusader army is massacred, and Baldwin is taken to the castle at Kharput. To save the situation the Venetians are asked to help. Doge Domenico Michiel lifts the siege of Corfu (see 1122) and takes his fleet to Acre, arriving at the port in the end of May.
- May – Baldwin II and Joscelin I are rescued by 50 Armenian soldiers (disguised as monks and merchants) at Kharput. They kill the guards, and infiltrate the castle where the prisoners are kept. Joscelin escapes to seek help. However, the castle is soon besieged by Turkish forces under Belek Ghazi – and is after some time recaptured. Baldwin and Waleran of Le Puiset are moved for greater safety to the castle of Harran.
- May 29 – Battle of Yibneh: A Crusader army led by Eustace Grenier defeats the Fatimid forces (16,000 men) near Ibelin. Despite the numerical superiority, Vizier Al-Ma'mun al-Bata'ihi is forced to withdraw to Egypt while his camp is plundered by the Crusaders. Eustace returns to Jerusalem in triumph, but later dies on June 15.
- May 30 – The Venetian fleet arrives at Ascalon and instantly set about attacking the Fatimid fleet. The Egyptians fall into a trap, caught between two Venetian squadrons, and are destroyed or captured. While sailing back to Acre, the Venetians capture a merchant-fleet of ten richly laden vessels.
- The Pactum Warmundi: A treaty of alliance, is established between the Kingdom of Jerusalem and the Republic of Venice at Acre. The Venetians receive a street, with a church, baths and a bakery, free of all obligations, in every town of the kingdom. They are also excused of all toll and taxes.
- August 29 – King Eystein I (Magnusson) dies during a feast at Hustad after a 20-year reign, leaving his brother Sigurd I (the Crusader) to rule over Norway.
- Sigurd I performs a Crusade, the Kalmare ledung, to Christianize the Swedish province of Småland. He makes a pact with King Niels of Denmark.
- May 9 – A fire in the city of Lincoln nearly destroys the Lincolnshire town; it is memorialized 600 years later by historian Paul de Rapin.
- August 9 – Battle of Al-Dimas: A Norman campaign in North Africa ends with their troops being massacred by Zirid forces near Mahdia (modern Tunisia).
- February 25 – Emperor Toba abdicates in favor of his 3-year-old son Sutoku after a 16-year reign. Retired-Emperor Shirakawa rules as regent over Japan.
- March 18 – First Council of the Lateran convenes in Rome; it confirms the Concordat of Worms (see 1122) and demands clerical celibacy in the Catholic Church.
- Diego Gelmírez, archbishop of Santiago de Compostela, declares an Crusade in Al-Andalus (modern Spain) against the Almoravids.
- The priory church of St Bartholomew-the-Great and St Bartholomew's Hospital (Barts) in London are founded by Rahere.
- Furness Abbey (or St Mary of Furness) is founded in England by Stephen, count of Boulogne, for the Order of Savigny.
- February 9 – Otto ( the Rich), count of Ballenstedt (b. 1070)
- March 4 – Peter of Pappacarbone, Italian abbot and bishop
- May 3 – Felicia of Roucy, queen of Aragon and Navarre
- June 15 – Eustace Grenier, French constable and regent
- July 18 – Bruno di Segni, Italian prelate and bishop
- August 29 – Eystein I (Magnusson), king of Norway
- September 11 – Marbodius of Rennes, French archdeacon
- September 19 – Taizu, emperor of the Jin Dynasty (b. 1068)
- September 27 – Fujiwara no Akisue, Japanese nobleman (b. 1055)
- December 14 – Henry IV, duke of Carinthia (House of Sponheim)
- Davyd Sviatoslavich, Kievan prince of Murom and Chernigov
- Henry II, margrave of Meissen and the Saxon Ostmark (b. 1103)
- Langri Tangpa, Tibetan Buddhist monk and master (b. 1054)
- Louis the Springer (Leaper), German nobleman (b. 1042)
- Steven Runciman (1952). A History of The Crusades. Vol II: The Kingdom of Jerusalem, p. 131. ISBN 978-0-241-29876-3.
- Steven Runciman (1952). A History of The Crusades. Vol II: The Kingdom of Jerusalem, pp. 132–133. ISBN 978-0-241-29876-3.
- Steven Runciman (1952). A History of The Crusades. Vol II: The Kingdom of Jerusalem, pp. 133–134. ISBN 978-0-241-29876-3.
- Steven Runciman (1952). A History of The Crusades. Vol II: The Kingdom of Jerusalem, p. 134. ISBN 978-0-241-29876-3.
- Steven Runciman (1952). A History of The Crusades. Vol II: The Kingdom of Jerusalem, p. 135. ISBN 978-0-241-29876-3.
- "Fires, Great", in The Insurance Cyclopeadia: Being an Historical Treasury of Events and Circumstances Connected with the Origin and Progress of Insurance, Cornelius Walford, ed. (C. and E. Layton, 1876) p.72.
- Meynier, Gilbert (2010). L'Algérie cœur du Maghreb classique: De l'ouverture islamo-arabe au repli (658-1518). Paris: La Découverte. p. 56.
- Johns, Jeremy (2002). Arabic administration in Norman Sicily: the royal dīwān. Cambridge University Press. p. 85. ISBN 0-521-81692-0.
- Fletcher, R. A. (1987). "Reconquest and Crusade in Spain c. 1050-1150". Transactions of the Royal Historical Society. 5. 37: 31–47 . JSTOR 3679149.