1173

Mieszko III (the Old) (c. 1126–1202)

Events

January 5 – Bolesław IV (the Curly), High Duke of Poland, dies after a 27-year reign. He is succeeded by his half-brother Mieszko III (the Old), and as duke of Sandomierz in Lesser Poland by Casimir II (the Just).
King Canute I (Knut Eriksson) extends his rule after the death of co-ruler Kol – which includes also Östergötland. He becomes the unopposed sole-ruler of Sweden. Canute is supported by Earl Birger Brosa.
Abu Yaqub Yusuf, caliph of the Almohad Caliphate, re-populates the western Andalusian city of Beja. But it is rapidly abandoned, a sign of the quick demographic weakening of the Muslims in the peninsula.<ref>Template:Cite book</ref>

Spring – Henry the Young King withdraws to the French court, marking the beginning of the Revolt of 1173–74, in which former Queen Eleanor of Aquitaine and her sons rebel against her ex-husband King Henry II.
October 17 – Battle of Fornham: Rebel forces are defeated while fording the River Lark. Flemish mercenaries are driven into the nearby swamps by the English royalists under Lord Richard de Luci (or Lucy).<ref>Beeler, John (1971). Warfare in Feudal Europe, 730–1200, pp 104–105. Ithaca, NY: Cornell University Press. Template:ISBN.</ref>

Summer – Saladin leads an expeditionary army against the Bedouin tribes in Oultrejordain to secure a route between Egypt and Syria. He raids the region at Kerak Castle.<ref>David Nicolle (2011). Osprey: Command 12 - Saladin, p. 4. Template:ISBN.</ref>
Pro-Fatimid rising in Upper Egypt led by Kanz al-Dawla, governor of Aswan, is crushed by Saladin's brother Al-Adil.

The Qiandao era ends and the Chunxi era begins during the reign of Emperor Xiao Zong of the Song dynasty.

South India

Sinhalese king Parakramabahu the Great gains a decisive victory by invading the Chola Empire as an ally of the Pandyas, capturing Tondi and Pasi regions.

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

King Béla III invites Cistercian and Premonstratensian monks to Hungary. They introduce advanced agricultural methods in the realm (approximate date).

February 21 – Thomas Becket is canonized by Pope Alexander III. His tomb in Canterbury Cathedral becomes a shrine and a popular pilgrimage destination.<ref name=CBH>Template:Cite book</ref>
Peter Waldo, French spiritual leader, is converted to Christianity and founds the Waldensians.
The Great Mosque of al-Nuri in Mosul is completed (approximate date).

Pedro Gudestéiz resigns the archdiocese of Santiago de Compostela after some controversy.<ref>Richard A. Fletcher, The Episcopate in the Kingdom of León in the Twelfth Century (Oxford University Press, 1978), p. 59.</ref>