Since February the rising had been getting every day more serious, and still no one was sent to supersede Lilburne. Cromwell at the outset of his reign felt the Scotch command was the most critical appointment he had to make. Not only was Scotland the chief field of Royalist action, but the Parliamentary army there was ultra-Independent, and sullenly disgusted to see a monarchy practically re-established. A man must go who could crush the Royalists speedily, and, which was still more important, who could be trusted with a victorious army of Irreconcilables afterwards. There was absolutely no one who fulfilled the conditions but Monk. In December it had been settled that he was to go, but till the Dutch war was over he could not be spared by the Admiralty. Day by day the news from the north grew worse, and still the Dutch struggled in Cromwell's grip to avoid the article for the seclusion of the Stuarts. At last it was done, and on April 6th, the very day after the treaty was signed, Monk got his route for Scotland with the fullest powers. A fortnight later he reached Dalkeith, and at once threw himself into the preliminary organisation of that forgotten campaign in which, if ever, the Highlands were for the first time conquered. It is a campaign of the highest interest, and well repays the laborious task of piecing it together from the obscure and confused notices that are extant. Hitherto Highland warfare had been little more than aimless hunts after an ever-shifting and disappearing objective. For the first time the rules of modern strategy were to be applied to it. The latest model for mountain warfare was the Duc de Rohan's brilliant Valtelline campaign of 1635. It was the admiration of all Europe, and has even been considered worthy of a commentary by the Archduke Charles himself. Two such professed soldiers as Monk and Middleton must have been perfectly familiar with it. Monk at least had studied the duke's _Perfect Captaine_ with an enthusiasm which his own _Observations_ too plainly betrays; and the scientific way in which he now went to work shows that he either invented or had learnt a thoroughly digested system.