- Financial and military pressures (scutages, aids, fines ect unpopular)
- Service overseas
- Excommunication? May have caused more trouble than we anticipate
- Personal grievances
- 1214 failure - John's allies defeated at Bouvines (John = bad military leader)
- Unfair taxes
- Harsh justice
- Extension of royal forests and forest law
- John aimed to bring all areas under personal supervision after 1204 and to ensure execution of policies throughout the lands which angered barons
- Appointed new men (often foreign) for office as he couldn't trust the old Northern families
- Seduced barons' wives and daughters

Rebels surprised John by capturing London May 1215 - John shocked by extent and rapidity of the rebellion
- Soon, Prince Louis of France joined the rebels in London (arrived May 1216)

The Northerners
Most affected area by June 1215 = North
This was because a few powerful men controlled an area and decided its allegiance
Most trouble in 1212 and 1213 originated in the North; in 1214 Northerners refused to support John's campaign abroad
This rebellion was more distinctively Northern than any revolt in Stephen or Henry's reign
Barons in the North exercised wide powers so felt constrained - John visited frequently to direct his power
Forest law was extended more in the North than any other region
Many Northern opposition barons were in debt to the crown

Clauses:
- 1 English Church free, its rights undiminished and liberties unimpaired
- 2 to 16 (excluding 13) concern the raising of money
- 2 - set the price of a barony at £100 (John had once charged as much as £10 000)
- 50 - removal of foreigners from their office (specifically names men such as Philp Marc and his brothers, and followers) - reflects the barons' xenophobic jealousy of specific individuals in John's government
- 29 - John can not take away deptors lands as he pleased 'no freeman shall be imprisoned or deprived of his freehold... expect by the lawful judgement according to his equals and law of the land"
First 15 designed to curb the King's exploitations in feudal custom - limiting scutage and relief payments ect

This was a rebellion against the arbitrary and exploitative tendencies of Angevin government as a whole, not just John
Half a century of Angevin government was the real problem, and Magna Carta was an inevitable reaction against this