 Over the next years , much of Hereford 's focus was on reconquering his lost lands in the Marches , primarily through private warfare against Llywelyn . Henry III died in 1272 , while his son – now Edward I – was crusading ; Edward did not return until 1274 . Llywelyn refused to pay homage to the new king , partly because of the military actions of Bohun and other Marcher lords , which Llywelyn saw as violations of the Treaty of Montgomery . On 12 November 1276 , Hereford was present at a royal assembly where judgment was passed on Llewelyn , and in 1277 , Edward I declared war on the Welsh prince . Rebellion in his own Brecon lands delayed Hereford 's participation in the early days of the Welsh war . He managed , however , to both suppress the rebellion , and conquer lands further west . He then joined up with the royal army and served for a while in Anglesey , before returning to Brecon , where he received the surrender of certain Welsh lords . After the campaign was over , on 2 January 1278 , he received protection from King Edward to go on pilgrimage to Santiago de Compostela in Spain . 
