1138

By place

Europe

• March 7 - Conrad III is elected as King of Germany in the presence of the papal legate Theodwin at Koblenz. He is crowned at Aachen six days later on March 13 and acknowledge in Bamberg by several German princes of southern Germany. Henry X, son-in-law and heir of the late King Lothair III, refuses his allegiance to Conrad. He is deprived of all his Saxon territories, which are given to Leopold IV.
• Summer - A civil war breaks out in the Holy Roman Empire, a struggle begins between the Guelphs and Ghibellines, while the family name Welf of Henry X will be corrupted into Guelph.
• October 20 - Bolesław III dies after a 31-year reign. He divides Poland among his sons: Władyslaw II receives Silesia and the Senioral territories – which includes the Kraków and Łęczyca regions, as well as parts of Kujawy and Wielkopolska. Bolesław IV receives Masovia and Mieszko III receives the newly established Duchy of Greater Poland. The 7-year-old Henry becomes duke of Sandomierz. Bolesław's last son, Casimir II receives nothing, as he is born after his father's death.

  England

• May - Earl Robert FitzRoy rebels against King Stephen, supporting Matilda in her claim for the English throne. Matilda is given refuge by Earl William de Albini at Arundel Castle. Stephen built siege works around the castle, but is unable to break the castle's defences. In France, Matilda's husband Duke Geoffrey V takes advantage of the situation by re-invading Normandy.
• August 22 - Battle of the Standard: King David I of Scotland gives his full support to Matilda, and invades the north of England – traveling as far south as Lincolnshire. The Scottish army is defeated by English forces under Earl William le Gros in Yorkshire. David retreats to Carlisle and reassembles an army.
• The Earldom of Pembroke, created for Gilbert de Clare, becomes the first earldom created by Stephen within the borders in Wales. Gilbert receives the rape and Pevensey Castle.

  Levant

• Spring - Emperor John II leads a Byzantine expeditionary force into Syria and arrives before the walls of Aleppo on April 20. The city proves too strong to attack, but the fortresses of Biza'a, Athareb, Maarat al-Numan and Kafartab are taken by assault. While the Byzantines besiege the city of Shaizar, the Crusader allies Prince Raymond of Poitiers of Antioch and Count Joscelin II of Edessa remain in their camp playing dice.
• Siege of Shaizar: The Byzantines under John II besiege the capital of the Munqidhite Emirate. They capture the lower city on May 20, but fail to take the citadel. John negotiates with Emir Abu'l Asakir Sultan – who sends him an offer to pay a large indemnity and becoming a vassal of the Byzantine Empire. John, disgusted by his Crusader allies, accepts the terms and raises the siege on May 21.
• October 11 - An earthquake in Aleppo, Syria, kills about 230,000 people.

  Asia

• November 5 - Lý Anh Tông is enthroned as emperor of Đại Việt at the age of two, starting a 37-year reign.

  By topic

Religion

• April 10 - Robert Warelwast is nominated as bishop of Exeter at a royal council in Northampton, England.