Here, the native Welsh clung on to their language, customs and laws, lords in their own lands, but still subjects of the English King. By the 13th century, Wales had become divided into the Principality of Gwynedd, the disputed centre, and the encroaching English baronial and crown lands. Encroaching, that is, until 1258, when Llewellyn was strong enough to have himself declared "Princeps Wallie" - Prince of Wales. Exploiting the civil war in England and making and allying with de Montfort, Llewellyn's armies overran the now undefended centre. But he then overreached himself, marrying de Montfort's daughter, an offence Edward was unlikely to forgive or to forget. Years later, Llewellyn handed Edward the perfect pretext for retribution. He failed to show up at Edward's coronation and ignored a total of five summonses to pay homage to his new King.


当地威尔士人坚持使用自己的语言，风俗，法律。虽然有自己的君王，却要向英格兰国王俯首称臣。到十三世纪时，威尔士被划分为三部分，格温内思公国，中部冲突地区，格温内思，以及英格兰贵族和国王渐进蚕食的地区。这种逐渐推进的入侵持续到1258年，此时卢埃林已积攒了足够的实力，自封为威尔士王子，借英格兰内战之机，以及与德·蒙德福特的结盟。卢埃林的军队占领了防守薄弱的中部地区，但随后他便得意忘形，迎娶了德·蒙德福特的女儿，这样的冒犯是爱德华不能宽恕和忘怀的。几年后，卢埃林就给了爱德华，一个报复的机会。他未出席爱德华的加冕礼，并且总共无视了五次传唤。拒不觐见新国王。