for describing any of the territory of Wales as a principality, although the term has occasionally been used in an informal sense to describe the country, and in relation to the honorary title of Prince of Wales. The Pre-Conquest Principality The Principality of Wales was created in 1216 at the Council of Aberdyfi, when it was agreed between Llywelyn the Great and the other sovereign princes among the Welsh that he was the paramount ruler amongst them, and they would pay homage to him. Later he obtained recognition, at least in part, of this agreement from the King of England, who agreed that Llywelyn's heirs and successors would enjoy the title "Prince of Wales" but with certain limitations to his realm and other conditions, including homage to the King of England as vassal, and adherence to rules regarding a legitimate succession. Llywelyn had been at pains to ensure that his heirs and successors would follow the "approved" (by the Pope at least) system of inheritance which excluded illegitimate sons. In so doing he excluded his elder bastard son Gruffydd ap Llywelyn from the inheritance, a decision which would have later ramifications. In 1240 Llywelyn died and Henry III of England (who succeeded John) promptly invaded large areas of his former realm, usurping them from him. However, the two sides came to peace and Henry honoured at least part of the agreement and bestowed upon Dafydd ap Llywelyn the title 'Prince of Wales'. This title would be granted to his successor Llywelyn in 1267 (after a campaign by him to achieve it) and was later claimed by his brother Dafydd and other members of the princely House of Aberffraw. Aberffraw Princes Llywelyn ap Iorwerth 1195–1240 By 1200 Llywelyn Fawr (the Great) ap Iorwerth ruled over all of Gwynedd, with England endorsing all of Llywelyn's holdings that year. England's endorsement was part of a larger strategy of reducing the influence of Powys Wenwynwyn, as King John had given William de Breos licence in 1200 to "seize as much as he could" from the native Welsh. However, de Breos was in disgrace by 1208, and Llywelyn seized both Powys Wenwynwyn and northern Ceredigon. In his expansion, the Prince was careful not to antagonise King John, his father-in-law. Llywelyn had married Joan, King John's illegitimate daughter, in 1204. In 1209 Prince Llywelyn joined King John on his campaign in Scotland. However, by 1211 King