Claim: Edward I of England responded to a second rebellion with a full-scale war of conquest.

The Conquest of Wales by Edward I , sometimes referred to as the Edwardian Conquest of Wales , Examples of historians using the term include Professor J.E. Lloyd , regarded as the founder of the modern academic study of Welsh history , in his History of Wales from the Earliest Times to the Edwardian Conquest , first published in 1911 , and Professor R.R. Davies , the leading modern scholar of the period , in his works including The Age of Conquest : Wales , 1063 -- 1415 , published 2000 . took place between 1277 and 1283 . It resulted in the defeat and annexation of the Principality of Wales , and the other last remaining independent Welsh principalities , by Edward I , King of England .   By the 13th century Wales was divided between native Welsh principalities and the territories of the Anglo-Norman Marcher lords . The leading principality was Gwynedd whose princes had gained control of the greater part of the country , making the other remaining Welsh princes their vassals , and had taken the title Prince of Wales . Although English monarchs had made several attempts to seize control of the native Welsh territories , it was not until Edward 's war of conquest against Llywelyn ap Gruffudd -LRB- `` Llywelyn the Last '' -RRB- of 1277 to 1283 that this was achieved on a lasting basis .   In two campaigns , in 1277 and 1282/1283 respectively , Edward first significantly reduced the territory of the Principality of Wales and then completely overran it , as well as the other remaining Welsh principalities . Most of the conquered territory was retained as a royal fief , and these lands subsequently became , by custom , the territorial endowment of the heir to the English throne with the title Prince of Wales . The remainder would be granted to Edward 's supporters as new Marcher lordships . Although the territories would not be effectively incorporated into the Kingdom of England until the Laws in Wales Acts 1535 -- 1542 , Edward 's conquest marked the end of Welsh independence .