1173

By area

Asia

• The Qiandao era ends, and the Chunxi era begins, of the Chinese Emperor Xiaozong of Song.
• Saladin seizes Aden in Arabia.

  Europe

• January 5 - On the death of Bolesław IV the Curly, High Duke of Poland, he is succeeded by Mieszko III the Old, and as Duke of Sandomierz in Lesser Poland by Casimir II the Just.
• March - Henry the Young King of England withdraws to the French court, marking the beginning of the Revolt of 1173–74, in which Eleanor of Aquitaine and her sons rebel against her husband Henry II of England.
• William de Braose, 3rd Lord of Bramber, becomes High Sheriff of Herefordshire in England.
• Abergavenny Castle is seized by the Welsh.
• Following the death of Kol, Canute I of Sweden extends his rule to also include Östergötland. He is now unopposed as king of Sweden.
• The efforts of the Almohad caliph, Abu Yaqub Yusuf, to repopulate the western Andalusian city of Beja begin. They are rapidly abandoned, sign of the quick demographic weakening of the Muslims in the peninsula.

  By topic

Arts and leisure

• August 8 - The construction of a campanile, which will become the Leaning Tower of Pisa, begins.
• Algebraic chess notation is first recorded.

  Religion

• February 21 - Canonisation of Thomas Becket: His tomb in Canterbury Cathedral becomes a shrine, and popular pilgrimage destination.
• Peter Waldo is converted to Christianity, and founds the Waldensians.
• Approximate traditional completion date of Great Mosque of al-Nuri.

  Births

• February/March - Conrad II, Duke of Swabia
• May 21 - Shinran, Japanese founder of Jōdo Shinshū Buddhism
• Llywelyn the Great, Prince of Aberffraw and Lord of Eryri
• Rostislav II of Kiev
• Isabella, Countess of Gloucester
• Tankei, Japanese sculptor

  Deaths

• January 5 - Bolesław IV the Curly, High Duke of Poland
• March 10 - Richard of Saint Victor, Scottish-born French mystic and theologian
• August 9 - Najm ad-Din Ayyub, father of Saladin
• October 6 - Engelbert III, Margrave of Istria
• October 15 - Petronilla of Aragon, queen regnant
• November 7 - Uijong of Goryeo, Korean monarch of the Goryeo dynasty
• date unknown
• * Roger de Clare, 2nd Earl of Hertford, Norman noble
• * Euphrosyne of Polotsk, abbess and saint
• * Vladimir III Mstislavich, Grand Prince of Kiev
• * Benoît de Sainte-Maure, French poet and troubadour
• * Kol of Sweden, ruler of Östergötland since 1167