* 1121 – Dirk VI becomes the Count of Holland.

* Ulrich of Eppenstein ( 1077 – 1121 )

* Manegold of Mammern ( 1121 – 1133 )

* Heinrich von Twiel ( 1121 – 1122 ) Anti-Abbot

* March 13 – Mieszko III, king of Poland ( b. c. 1121 )

William the Aetheling having perished in the wreck of the White Ship ( 25 November 1120 ), Fulk, on his return from a pilgrimage to the Holy Land ( 1120 – 1121 ), married his second daughter Sibyl, at the instigation of Louis VI, to William Clito, son of Robert Curthose, and a claimant to the duchy of Normandy, giving her Maine for a dowry ( 1122 or 1123 ).

* 1121 – Al-Khazini publishes The Book of the Balance of Wisdom, in which he invents a hydrostatic balance for measuring specific gravity, and proposes that the gravity and gravitational potential energy of a body vary depending on its distance from the centre of the Earth.

In the years 1121 – 1122 Pomerania became a Polish fief and a local strongman, Prince Wartislaw I swore feudal allegiance to the Polish monarch and undertook to pay a yearly tribute of 500 marks of silver to Poland ( One mark of silver was equal to 240 denarii.

In 1119 – 1121 John defeated the Seljuq Turks, establishing his control over southwestern Anatolia.

**# Henry ( 1121 – 75 ), archbishop of Reims

* Alfonso ( b. 1120 / 1121 – d. 10 October 1144 ), Prince of Capua ( from 1135 ) and Duke of Naples ;

164 ( 11 ): 1121 – 1123.

Adeliza of Louvain, sometimes known in England as Adelicia of Louvain, also called Adela and Aleidis ; ( c. 1103 – 23 April 1151 ) was queen consort of the Kingdom of England from 1121 to 1135, the second wife of Henry I.

** Third son: Imperial Prince Koreaki ( 惟明親王 ) ( 1172 – 1121 ), later Imperial Prince and Monk Shōen ( 聖円入道親王 )

* William of Champeaux ( 1070 – 1121 ), French philosopher and theologian

* Alpheus: A river associated with Olympia, home of The Olympic Games – a breathless, gasping runner is said to be breathing it ( line 1121 ).

* P. 1121 – a Hawker project

| width = auto | Floris IIthe Fat1091 – 1121

In the winter of 1120 – 1121 the Georgian troops successfully attacked the Seljuk settlements on the eastern and southwestern approaches to the Transcaucasus.

In 1121, Sultan Mahmud b. Muhammad ( 1118 – 1131 ) declared a holy war on Georgia and rallied a large coalition of Muslim states led by the Artuqid Najm al-din El-ğazi and Toğrul b. Muhammad.

Guillaume de Champeaux ( c. 1070 – 18 January 1121 in Châlons-en-Champagne ), also known as William of Champeaux ( English ) or Guglielmus de Campellis ( Latin ), was a French philosopher and theologian.

* 1121 – Al-Khazini: variation of gravitation and gravitational potential energy at a distance ; the decrease of air density with altitude

* 1121 – Al-Khazini makes extensive use of the experimental method to prove his theories on mechanics in The Book of the Balance of Wisdom

* Hugh le Roux ( 1121 – 1171 )

* 1121: On August 12, in the Battle of Didgori, the greatest military victory of Georgia, King David the Builder with 40, 000 Georgians, 15, 000 Kipchak auxiliaries, 500 Alan mercenaries and 300 French Crusaders defeats a Seljuk-led Muslim coalition army of 400, 000.

In the area of Gryfice the Battle of Niekładź took plcace in 1121, in which Polish ruler Bolesław III Krzywousty defeated Wartislaw I, Duke of Pomerania and Swantopolk I, Duke of Pomerania

Popularly considered to be the greatest and most successful Georgian ruler in history, he succeeded in driving the Seljuk Turks out of the country, winning the major Battle of Didgori in 1121.

The famous Battle of Didgori took place on 12 August 1121.

In 1121 a Seljuq-Artuqid alliance, commanded by Mehmed I of Great Seljuq and Ilghazi, was defeated by Georgia at the Battle of Didgori.

The Battle of Didgori () was fought between the armies of the Kingdom of Georgia and the crumbling Great Seljuq Empire at the place of Didgori, 40 km west of Tbilisi, ( the modern-day capital of Georgia ), on August 12, 1121.

Alexander Mikaberidze, "‘ Miraculous Victory :’ Battle of Didgori, 1121 ," Armchair General ( May 14, 2008 )

However, 12 August 1121, King David routed the enemy army on the fields of Didgori, achieving what is often considered the greatest military success in Georgian history.

As a commander, he took part in his father ’ s battles, particularly at Didgori ( 1121 ) and Shirvan ( 1123 ).

This combined army under the overall command of Ilghazi entered the valley of Trialeti in eastern Georgia and encamped in the vicinities of Didgori and Manglisi in mid-August 1121.

Didgori 1121

Didgori 1121

pl: Bitwa pod Didgori ( 1121 )

It was a site of the celebrated victory won by the Georgian king David IV over the Seljuk armies on August 12, 1121.

By June 1121, Tbilisi had actually been under a Georgian siege, with its Muslim élite being forced into paying a heavy tribute to David IV.

Three years afterwards, under Yusuf's son and successor, Ali ibn Yusuf, Sintra and Santarém were added, and Iberia was again invaded in 1119 and 1121, but the tide had turned, the French having assisted the Aragonese to recover Zaragoza.

It was founded by Henry I in 1121 " for the salvation of my soul, and the souls of King William, my father, and of King William, my brother, and Queen Maud, my wife, and all my ancestors and successors ".

It was refurbished in 1121, during the reign of King Henry I, and responsibility for its maintenance was transferred to the city of Lincoln by King James I.

During the reign of King Henry I the canal is recorded as having been scoured out to increase its depth in 1121, but it deteriorated until by the 17th century it was virtually impassable.

By 1110, important crown wearings ( Great Council of state ) were noted as taking place at the castle and King Henry married his second wife there in 1121, after the ' White Ship ' disaster.

In 1121 King Henry 1 founded the great Abbey of Reading and endowed it with many gifts of land, including the Manor of Thatcham.

In 1121, King Henry I founded Reading Abbey which grew to become one of the most important religious and political centres of England.

Domhnall Ua Lochlainn ( old spelling: Domnall Ua Lochlainn ) ( 1048 – 10 February 1121 ), also known as Domhnall Mac Lochlainn ( old spelling: Domnall Mac Lochlainn ), claimed to be High King of Ireland.