Royal power in Wales was unevenly applied, with the country divided between the marcher lords along the borders, royal territories in Pembrokeshire and the more independent native Welsh lords of North Wales. John took a close interest in Wales and knew the country well, visiting every year between 1204 and 1211 and marrying his illegitimate daughter, Joan, to the Welsh prince Llywelyn the Great. The king used the marcher lords and the native Welsh to increase his own territory and power, striking a sequence of increasingly precise deals backed by royal military power with the Welsh rulers. A major royal expedition to enforce these agreements occurred in 1211, after Llywelyn attempted to exploit the instability caused by the removal of William de Braose, through the Welsh uprising of 1211. John's invasion, striking into the Welsh heartlands, was a military success. Llywelyn came to terms that included an expansion of John's power across much of Wales, albeit only temporarily.
What did John use to increase his own territory and power?
marcher lords and the native Welsh