Why did war between Edward I and Wales begin again in 1282?

The war between Edward I and the Welsh in 1282 was primarily triggered by a deterioration in relations between the English king and a number of Welsh princes.1

Following the conflict of 1277, which had severely restricted the power of Llywelyn ap Gruffudd to the region of Gwynedd west of the Conwy, tensions persisted regarding English rule and the status of the Welsh territories. When this English administration provoked rebellion, Llywelyn and his brother David ap Gruffudd raised a revolt in 1282 to fight for national independence. Although Llywelyn may not have been the original instigator of the uprising, he placed himself at its head to pursue his long-standing aspirations for Welsh unity and a stabilized relationship with England. The conflict ultimately resulted in the death of Llywelyn in 1282 and the collapse of Welsh resistance by the summer of 1283.123