How did the Battle of Bouvines weaken King John of England?

The Battle of Bouvines on July 27, 1214, was a decisive defeat for the coalition organized by King John of England, which included Holy Roman emperor Otto IV and various French vassals.1

The defeat significantly weakened King John in the following ways:

• Loss of Territory: The failure of the coalition, combined with John’s earlier defeat at La Roche-aux-Moines, confirmed that Philip II held possession of most former English lands in France, effectively dismantling the Angevin Empire.1
• Financial and Political Instability: John’s military efforts were extremely costly, leading to unpopular taxation and the aggressive collection of inheritance duties. The collapse of his campaign left him financially drained and politically isolated.12
• Baronial Opposition: Following the defeat, John faced intense pressure from his disgruntled barons, who had already opposed his service in Poitou and his disregard for law and custom. This mounting opposition forced him to sign the Magna Carta in 1215 as a desperate attempt to address their grievances.12