Editing First Barons' War (section)

{{No footnotes|date=March 2025}}
{{short description|Civil war in the Kingdom of England}}
{{Use British English|date=May 2012}}
{{Use dmy dates|date=July 2021}}
{{Infobox military conflict
| conflict          = First Barons' War
| partof            = the  [[First Hundred Years' War]]
| image             = John of England vs Louis VIII of France.jpg
| image_size        = 300
| caption           = King John of England (left) in battle with the troops of Louis of France (right)
| date              = 1215–1217
| place             = England
| casus             = Baronial discontent with government of [[John of England|King John]]
| result            = Victory of the [[Angevin kings of England|English monarchy]]
* [[Treaty of Lambeth]]
* Restoration of ''[[Magna Carta]]''
| combatant1        = [[Kingdom of England]]
| combatant2        = {{indented plainlist|
*[[Marshal of the Army of God and Holy Church|Army of God and Holy Church]]
*[[Kingdom of France]]
----
Supported by:
*[[Kingdom of Scotland]]}}
| combatant3        = 
| commander1        = {{indented plainlist|
* [[John of England|King John]]{{Natural Causes}}
* [[Hubert de Burgh, 1st Earl of Kent|Hubert de Burgh]]
* [[William Longespée, 3rd Earl of Salisbury|William Longespée]]
* [[Ranulf de Blondeville, 6th Earl of Chester|Ranulf de Blondeville]]
* [[Peter des Roches]]
* [[William de Ferrers, 4th Earl of Derby|William de Ferrers]]
* [[William Marshal, 2nd Earl of Pembroke|William Marshal]] (from March 1217)}}
| commander2        = {{indented plainlist|
* Prince [[Louis VIII of France|Louis of France]]
* [[Robert, Lord of Champignelles]]
* [[Robert Fitzwalter]]
* [[Saer de Quincy, 1st Earl of Winchester|Saer de Quincy]]
* [[Gilbert de Clare, 5th Earl of Gloucester|Gilbert de Clare]]
* [[Henry de Bohun, 1st Earl of Hereford|Henry de Bohun]]
* [[William Marshal, 2nd Earl of Pembroke|William Marshal]] (until March 1217)
* [[Thomas, Count of Perche]]{{KIA}}
* [[Eustace the Monk]]{{Executed}}}}
| commander3        = 
| strength1         = 
| strength2         = 
| strength3         = 
| casualties1       = 
| casualties2       = 
| casualties3       = 
| notes             = 
| campaignbox       = {{Campaignbox First Barons' War}}
{{Campaignbox Barons' Wars}}
{{Campaignbox Anglo-French wars}}
}}

The '''First Barons' War''' (1215–1217) was a civil war in the [[Kingdom of England]] in which a group of rebellious major landowners (commonly referred to as [[English feudal barony|barons]]) led by [[Robert Fitzwalter]] waged war against [[John of England|King John of England]]. The conflict resulted from King John's disastrous wars against King [[Philip II of France]], which led to the collapse of the [[Angevin Empire]], and John's subsequent refusal to accept and abide by [[Magna Carta]], which John had sealed on 15 June 1215.

The rebellious barons, faced with an uncompromising king, turned to King Philip's son, [[Louis VIII of France|Louis]], who, in 1216, then sailed to England with an army despite his father's disapproval, as well as the pope's, who subsequently excommunicated him. Louis captured [[Winchester]] and soon controlled over half of the English kingdom.{{sfn|Harding|1993|p=10}} He was proclaimed "King of England" in London by the barons, although he was never actually crowned.

Louis's ambitions of ruling England faced a major setback in October 1216, when John's death led to the rebellious barons deserting him in favour of John's nine-year-old son, [[Henry III of England|Henry III]], and the war dragged on. Louis's army was finally beaten at the [[Battle of Lincoln (1217)|Battle of Lincoln]] on 20 May 1217. After a fleet assembled by his wife, [[Blanche of Castile]], attempted to bring him French reinforcements but was [[Battle of Sandwich (1217)|defeated off the coast of England at Sandwich]] on 24 August 1217, he was forced to make peace on English terms. He signed the [[Treaty of Lambeth]] and surrendered the few remaining castles that he held. The treaty had the effect of Louis agreeing he had never been the legitimate king of England. That formalised the end of the civil war and the departure of the French from England.{{sfn|Arlidge|Judge|2014|p=19}}