[Sidenote: Continued war with Wales. 1094.] In the neighbourhood of Wales, too, fighting was almost perpetual. Not only did the great Earldoms of Shrewsbury and Chester increase their borders, but many knights took advantage of the frequent civil divisions of the Welsh to push westward and set up their castles. The course of the war had lately been in favour of the Welsh rather than of the Normans, and in 1095 William thought it necessary to lead an army against them. His attempt was not successful, nor was a repetition of it two years later more so. The nature of the ground was too difficult for the advance of a great army, and William, thus a second time repelled, had again to trust to the self-interest and courage of individual Norman settlers. This plan he strengthened by granting to Normans portions of land as yet unconquered. Thus two members of the house of Montgomery, brothers of Hugh, Earl of Shrewsbury, Roger and Arnulf, did homage for lands in Powys and Dyfed, and Hugh de Lacy for lands to the west of Herefordshire. This guerilla warfare was successful, and Hugh of Chester was just succeeding in winning back Anglesey, which had been taken from him, when an invasion of Magnus of Norway checked for the time the Norman success. The Earl of Shrewsbury, while assisting Hugh of Chester, lost his life, and was succeeded by Robert de Belesme, his brother. On the whole, the English frontier constantly advanced, and the border counties were thronged with castles either of the great Earls or of individual adventurers. [Sidenote: Troubles in Normandy. 1094.] [Sidenote: Conspiracy of Mowbray crushed.] [Sidenote: William obtains Normandy from Robert. 1096.] [Sidenote: Size of his dominions at his death, 1100.]