1171 CE
King Henry II decides to lead a military expedition to Ireland and summons Richard de Clare (Strongbow) to join forces. In September, Richard travels to England and promises his loyalty to Henry. He is granted Leinster as a fiefdom and is honored with the post of "royal constable in Ireland". The army is assembled at Pembroke – several siege towers are shipped over, should Henry need to assault the Norman-held towns (or others such as Cork and Limerick). Caliph Al-Adid dies of natural causes (or poisoning) after a 11-year reign. Saladin overthrows the Fatimid Caliphate, and takes over as governor (atabeg) of Egypt – ruling in the name of Emir Nur al-Din. Henry II invades Ireland and lands with a large army of at least 500 mounted knights, and 4,000 men and archers at Waterford. Henry commandeers merchant ships as part of his invasion. He claims the ports of Dublin, Waterford, and Wexford, and promises the Irish chieftains protection if they will acknowledge him as their overlord. Henry is recognized as "Lord of Ireland", traders are invited to Dublin where an English colony is set up.
In the 1170s, the 12th century.
Geopolitics & Diplomacy
- March 10 – King Amalric I of Jerusalem departs with a large staff for Constantinople. At Callipolis he is met by his father-in-law, John Doukas Komnenos, military governor (doux) of Cyprus. Amalric enters the Byzantine capital and is welcomed by Manuel I. In June, a treaty is signed, Amalric recognizes Manuel's suzerainty over Jerusalem.source
- The successors of Robert Bordet leave Catalonia for Mallorca, marking the end of the attempts to create a Norman principality in Iberia.source
Conflict & Security
- March 12 – Emperor Manuel I (Komnenos) orders the arrest of all Venetians in his empire, and seizes their ships and goods.source
- May – following the death of Diarmait Mac Murchada, King of Leinster, the lordship of Leinster is disputed between his son, Domhnall Caomhánach, and the Cambro-Norman Richard de Clare (Strongbow).Irelandsource
- September 25 – Saladin leads an Egyptian army to take part in a joint attack on the Crusader castles Kerak and Montréal, south of the Dead Sea. In November, Saladin withdraws his forces to Cairo to suppress a coup.source
- October 17 – Henry II invades Ireland and lands with a large army of at least 500 mounted knights, and 4,000 men and archers at Waterford. Henry commandeers merchant ships as part of his invasion. He claims the ports of Dublin, Waterford, and Wexford, and promises the Irish chieftains protection if they will acknowledge him as their overlord. Henry is recognized as "Lord of Ireland", traders are invited to Dublin where an English colony is set up.source
- Ascall mac Ragnaill, last Norse–Gaelic King of Dublin, is captured while trying to retake Dublin from de Clare, perhaps in company with Sweyn Asleifsson, and beheaded; before the end of the year, de Clare relinquishes possession of the city to his own liege lord, Henry.Irelandsource
Exploration & Expansion
- July – King Henry II decides to lead a military expedition to Ireland and summons Richard de Clare (Strongbow) to join forces. In September, Richard travels to England and promises his loyalty to Henry. He is granted Leinster as a fiefdom and is honored with the post of "royal constable in Ireland". The army is assembled at Pembroke – several siege towers are shipped over, should Henry need to assault the Norman-held towns (or others such as Cork and Limerick).source
Religion & Belief
Health & Medicine
- September – Doge Vitale II Michiel leads a Venetian fleet (120 ships) against the Byzantines, conquering the cities of Trogir and Dubrovnik. But the plague takes a heavy toll among the fleet's crewmen; half the ships have to be burned to keep them from falling into enemy hands. A plague also breaks out in Venice, when the remaining ships return.source
Culture & Society
- Yesugei (Baghatur), Mongol chieftain, arranges a marriage between his 9-year-old son Temujin (Genghis Khan) and the daughter of the chief of a nearby clan, Börte. He is poisoned by the Tatars while returning home.source
Births
- August 15 – Alfonso IX, king of León and Galicia (died 1230)source
- Minamoto no Michitomo, Japanese nobleman (died 1227)source
- Agnes of France (or Anna), Byzantine empress (died 1220)source
- Saionji Kintsune, Japanese nobleman and poet (died 1244)source
- Muhammad Aufi, Persian historian and philologist (died 1242)source
- Matilda of Chester (or Maud), English noblewoman (died 1233)source
- Stephen de Segrave, English Chief Justiciar (died 1241)source
- Al-Aziz Uthman, Egyptian ruler and son of Saladin (died 1198)source
Deaths
- February 20 – Conan IV ("the Young"), duke of Brittany (born 1138)source
- March 29 – Achard of Saint Victor, Norman bishop (born 1100)source
- April 3 – Philip of Milly, French nobleman and knight (born 1120)source
- May 1 – Diarmaid mac Murchadha, king of Leinster (born 1110)source
- 1 May – Diarmait Mac Murchada, King of Leinster (born 1110).Irelandsource
- June 9 – Jacob ben Meir Tam, French Jewish rabbi (born 1100)source
- August 8 – Henry of Blois, bishop of Winchester (born 1096)source
- September 13 – Caliph Al-Adid dies of natural causes (or poisoning) after a 11-year reign. Saladin overthrows the Fatimid Caliphate, and takes over as governor (atabeg) of Egypt – ruling in the name of Emir Nur al-Din.source
- September 13 – Al-Adid, last Fatimid caliph (born 1151)source
- November 8 – Baldwin IV, count of Hainaut (born 1108)source
- December 27 – Petrus Ua Mórda, bishop of Clonfertsource
- Ascall mac Ragnaill (or Torcaill), last Norse–Gaelic king of Dublin, is captured while trying to retake Dublin from the English forces under Richard de Clare, perhaps in company with Sweyn Asleifsson, and is beheaded. Before the end of the year, Richard relinquishes possession of the city to Henry II, who converts it into an English royal town.source
- Ascall mac Ragnaill (or Torcaill), king of Dublinsource
- Narathu, ruler of the Pagan Kingdom (born 1118)source
- Yesugei ("Baghatur"), Mongol chieftain (born 1134)source
- Ascall mac Ragnaill, King of Dublin.Irelandsource