This was the end of William's troubles in England which have any real connexion with the Conquest. Malcolm of Scotland invaded Northumberland once more, and harried that long-suffering region, but without result; and an army of English barons, led by the king's son Robert, which returned the invasion soon after, was easily able to force the king of the Scots to renew his acknowledgment of subjection to England. The failure of Walcher, Bishop of Durham, to keep his own subordinates in order, led to a local riot, in which the bishop and many of his officers and clergy were murdered, and which was avenged in his usual pitiless style by the king's brother Odo. William himself invaded Wales with a large force; received submissions, and opened the way for the extension of the English settlements in that country. The great ambition of Bishop Odo, and the increase of wealth and power which had come to him through the generosity of his brother, led him to hope for still higher things, and he dreamed of becoming pope. This was not agreeable to William, and may even have seemed dangerous to him when the bishop began to collect his friends and vassals for an expedition to Italy. Archbishop Lanfranc, who had not found his brother prelate a comfortable neighbour in Kent, suggested to the king, we are told, the exercise of his feudal rights against him as his baron. The scene must have been a dramatic one, when in a session of the curia regis William ordered his brother's arrest, and when no one ventured to execute the order laid hands upon him himself, exclaiming that he arrested, not the Bishop of Bayeux, but the Earl of Kent. William must have had some strong reason for this action, for he refused to consent to the release of his brother as long as he lived. At one time what seemed like a great danger threatened from Denmark, in the plans of King Canute to invade England with a vast host and deliver the country from the foreigner. William brought over from Normandy a great army of mercenaries to meet this danger, and laid waste the country along the eastern coast that the enemy might find no supplies on landing; but this Danish threat amounted to even less than the earlier ones, for the fleet never so much as appeared off the coast. All these events are but the minor incidents which might occur in any reign; the Conquest had long been finished, and England had accepted in good faith her new dynasty.