Monarch - Stephen (to 8 April 1141), Matilda (to 1 November 1141), Stephen
Events
1140
December - The Anarchy: Earl Ranulf of Chester captures Lincoln.
Dryburgh Abbey founded.
1141
2 February - The Anarchy: At the First Battle of Lincoln, Robert, 1st Earl of Gloucester and Empress Matilda wrest control of the throne from King Stephen.
8 April - The Anarchy: Stephen captured and Matilda proclaimed "Lady of the English".
24 June - The Anarchy: Matilda is forced to flee Westminster during a royal banquet, and flees to Oxford.
July - The Anarchy: Matilda I of Boulogne, wife of Stephen, recaptures London.
14 September - The Anarchy: Rout of Winchester: Robert of Gloucester captured by forces loyal to Stephen during fighting at Winchester.
1 November - The Anarchy: Stephen and Robert exchanged as prisoners ending the reign of Matilda.
1142
Matilda grants the church of Oakley, Buckinghamshire, with its chapels of Brill, Boarstall and Addingrove, to the monks of the Priory of St Frideswide, Oxford.
Matilda's son Henry comes to England for the first time.
26 September - The Anarchy: Stephen captures Oxford, and besieges Matilda inside the castle.
December - The Anarchy: Matilda escapes from Oxford Castle across the snow in a white cape for camouflage, according to Henry of Huntingdon.
1143
The Anarchy: Geoffrey de Mandeville, a supporter of Matilda, is deprived of his castles in Essex, but subsequently captures Ely and campaigns in Cambridgeshire.
Robert of Ketton makes the first European translation of the Qur'an into Latin.
1144
11 February - Robert of Chester completes the translation of Book of the Composition of Alchemy from Arabic to Latin. It is the first book in Europe to describe alchemy.
22 March - A young apprentice, William of Norwich, is murdered, a crime attributed to the Jews by the Norwich mob, the first known medieval accusation of blood libel against Jews.
28 November - 24 December - The Siege of Edessa by Muslims led by Imad ad-Din Zengi eliminates the Crusader principality of Outremer, the news causing the pope to preach a new Crusade.
Matilda's husband Geoffrey V of Anjou, completes the conquest of Normandy.
1145
The Anarchy: Stephen captures Faringdon Castle.
Woburn Abbey founded.
Robert of Chester makes the first translation of an algebra text from Arabic into Latin.
1146
The Anarchy: Ranulf of Chester is captured, but released after surrendering his castles.
Many knights and barons leave England to take part in the Second Crusade.
1147
The Anarchy: Henry arrives in England to fight for Matilda, but is defeated in skirmishes, and returns to Normandy.
The Anarchy: Ranulf of Chester lays waste to the land around Coventry, but fails to capture the city itself.
24 October - English crusaders capture Lisbon from the Moors.
1148
February - The Anarchy: Empress Matilda forced to return to Normandy.
1149
22 May - King David I of Scotland knights Henry, and cedes northern Lancashire to Ranulf of Chester, in return for control of Carlisle.
King David I of Scotland attempts to wrest control of the Bishopric of Durham and the Archbishopric of York from Stephen, but fails.
Births
1140
William FitzRalph, future Sheriff of Nottingham and seneschal of Normandy
1146
William Marshal, 1st Earl of Pembroke, soldier and statesman (died 1219)
1147
Hugh de Kevelioc, 3rd Earl of Chester (died 1181)
Deaths
1140
6 February - Thurstan, Archbishop of York (born c. 1070 in Normandy)
1141
Aubrey de Vere, Lord Great Chamberlain (born 1062)
1142
Orderic Vitalis, chronicler (born 1075)
1143
William of Malmesbury, historian (born 1080)
1144
Geoffrey de Mandeville, 1st Earl of Essex
1147
31 October - Robert, 1st Earl of Gloucester, politician (born c. 1090)
1148
3 January - Anselm of St Saba, abbot of Bury St Edmunds (born 1136 in Italy)
6 January - William de Warenne, 3rd Earl of Surrey (born 1119; killed on crusade)
Gilbert de Clare, 1st Earl of Pembroke (born c. 1100)