[3] John was supported by the bulk of the English and Norman nobility and was crowned king at Westminster, backed by his mother, Eleanor of Aquitaine.

[6] The Norman frontiers had limited natural defences but were heavily reinforced with castles, such as Château Gaillard, at strategic points, built and maintained at considerable expense.

[7] It was difficult for a commander to advance far into fresh territory without having secured his lines of communication by capturing these fortifications, which slowed the progress of any attack.

[10] The new peace, the Treaty of Le Goulet, would only last for two years; war recommenced in the aftermath of John's decision in August 1200 to marry Isabella of Angoulême.

[12] Unfortunately, Isabella had already been engaged to be married to Hugh IX of Lusignan, an important member of a key Poitou noble family and brother of Raoul, the count of Eu, who possessed lands along the sensitive eastern Normandy border.

[11] Just as John stood to benefit strategically from marrying Isabella, so the marriage threatened the interests of the Lusignans, whose own lands currently provided the key route for royal goods and troops across Aquitaine.

[12] Hugh did exactly this in 1201 and Philip summoned John to attend court in Paris in 1202, citing the Le Goulet treaty to strengthen his case.

[12] John initially adopted a defensive posture similar to that of 1199: avoiding open battle and carefully defending his key castles.

Despite de Roches being a powerful Anjou noble, John largely ignored him, causing considerable offence, whilst the king kept the rebel leaders in such bad conditions that twenty-two of them died.

[16] As the situation became worse for John, he may have decided to have Arthur killed (though proof is lacking), to remove his potential rival and of undermining the rebel movement in Brittany.

[21] Arthur's sister, Eleanor, who had also been captured at Mirebeau, was kept imprisoned by John for many years, albeit in relatively good conditions.

[24] His use of routier mercenaries in the central regions had rapidly eaten away his remaining support in this area too, which set the stage for a sudden collapse of Angevin power.

[25][nb 4] John retreated across the Channel in December, sending orders for the establishment of a fresh defensive line to the west of Chateau Gaillard.

[citation needed] Following this decisive defeat, John faced unrest in his kingdom, and was forced to sign Magna Carta to appease the English nobility.