In 1204, Philip II of France had forced King John out of continental Normandy enforcing his 1202 claim that the lands were forfeit. Despite the 1217 Treaty of Lambeth, hostilities continued between the successive Kings of France and England until 1259.
Under the Treaty, Henry acknowledged loss of the Duchy of Normandy. However, Philip had failed in his attempts to occupy the Norman islands in the Channel. The treaty held that "islands (if any) which the King of England should hold", he would retain "as peer of France and Duke of Aquitaine" (these islands came to be collectively called the Channel Islands, consisting of Jersey, Guernsey, Alderney, Sark and some smaller islands).
Henry agreed to renounce control of Maine, Anjou and Poitou, which had been lost under the reign of King John but remained Duke of Aquitaine and was able to keep the lands of Gascony and parts of Aquitaine but only as a vassal to Louis.
In exchange, Louis withdrew his support for English rebels. He also ceded to Henry the bishoprics and cities of Limoges, Cahors and Périgueux and was to pay an annual rent for possession of Agenais.