Cromwell had now other work for his most trusted officer. General Middleton had landed in Scotland to fan the flame which Lord Glencairn had kindled for the King, and which Morgan had nearly smothered. The Highlands were in a blaze, the Lowlands were seething in the heat, and Lilburne showed himself incapable of coping with the growing danger in spite of the fiery little dragoon's assistance.
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.
His general idea was to out the Highlands asunder along the line of what is now the Caledonian Canal, and to fix his enemy within one of two definite areas, where he could operate against him as he chose. The area to the north of the line was sufficiently determined by its geographical conformation, but that to the south had to be firmly marked by strategical positions. Already a chain of fortresses and strong posts stretching from Inverness through Stirling to Ayr shut it in on the south and east, and during the next two months, while Monk was waiting for the grass to grow sufficiently for him to be able to move his cavalry, the investment was completed. On the west, from Glencoe to the head of Loch Lomond, diplomacy secured Argyle's country in a state of armed neutrality, and at each of the four salient angles of the area was established an independent base. One was at Inverness, one at Perth, and a third at Kilsyth, between Stirling and Glasgow, with Leith for its supporting base. The fourth by a bold stroke was to be planted in the heart of the enemy's country at Lochaber, with supporting bases at Liverpool and Ayr, whereby he would complete his quadrilateral and secure the southern end of his dividing line. From these points he intended to act on double lines of operation, with two strong columns keeping light touch with one another, and each able at any moment to act in a new direction by a rapid change of base. One of them he was to lead himself, while Morgan took command of the other. Their organisation was a source of the greatest care. As he was not likely to meet horse in any numbers, Monk boldly eliminated from the foot nearly the whole of the pikes on which the steadiness of infantry was supposed to depend, and filled his ranks almost entirely with musketeers.
To the labour of laying this elaborate foundation for the campaign was added the task of reducing the army to some sense of discipline. Monk had found it badly demoralised by the incapacity of Lilburne, and the license which he had allowed to religious controversy. On all this he set his foot, and at the same time endeavoured to repair the mischief which the wanton insolence of the sectaries had done, by inaugurating a conciliatory policy towards the Scots—a policy, however, which he was careful to fortify by a system of strong patrols in the Lowlands.
At present there was no need to press offensive operations. Middleton was still in Sutherland, and from Dingwall Morgan was watching him, ready to fall on him if he attempted to join the Lochaber chiefs. In the middle of May Monk moved to Stirling to see that all the outlets from the hills were sufficiently secured to prevent forays in that direction. Having ordered the construction of redoubts and the staking of fords wherever necessary, he joined the first column at Kilsyth in order to more deeply mark the south-west limit of his southern area by operations in the Ben Lomond hills. First, however, an important step was taken. A column, consisting of two thousand men and furnished with all necessary materials for establishing the fourth base, was being secretly organised in Ireland to seize Inverlochy. The time was now ripe for the attempt, and Colonel Brayne was despatched to bring it over. This done, Monk commenced his work. The difficulties of the undertaking at once declared themselves. The moment he moved, Glencairn, who occupied the Ben Lomond country, began raiding in his rear and stopped him. But the veteran of the Irish wars had learnt when to be bold, and without hesitation he flew at his enemy's throat. Advancing resolutely over the Kilsyth hills and up the headwaters of the Forth into the heart of the Ben Lomond range, he compelled Glencairn to concentrate and occupy a strong position at Aberfoyle. Here Monk attacked him. Again and again he was repulsed. But the discipline of the "red soldier" told at last, and Glencairn had to give way. The hills were cleared, every boat on the loch destroyed, and the western boundary of the southern area completed with an impassable stretch of water from Argyle's country to the banks of the Clyde.
Meanwhile Middleton had outwitted Morgan. Breaking up his force he had slipped it piecemeal over the hills and had joined his friends in Lochaber. It was the signal for active operations. Leaving a small force to cover Glasgow, and ordering up the Border horse under Colonel Howard in support, Monk suddenly shifted on to the Perth line and plunged into the hills. He meant if possible to drive the enemy through the gap he had left into the Lowlands, where they would fall an easy prey to his horse, or, if that failed, to force them northward. Moving with startling rapidity he was soon entangled in the wildest of the enemy's mountains and morasses. It was a country which till Deane's demonstration two years ago had been considered inaccessible to Lowland troops. It swarmed with roving bands of Highlanders; every straggler was a doomed man; the horse could hardly move, and the whole work of the march was arduous beyond all experience. But bold as was Monk's project its execution was cautious in the extreme. Every step of the way he made good. The country was systematically ravaged and every castle of strategic importance captured, garrisoned, and turned into an advanced magazine, according to the somewhat cumbrous and pedantic system which Monk and his contemporaries were then introducing. To prevent surprise and give time for properly securing his quarters he never marched after mid-day, nor did he ever move without flanking parties and a cloud of scouts. He marked out each camp and placed every picket and sentry himself, and was, in short, the head and heart alike of his over-worked force.
Indifferent to hunger and sleep himself, he took every care of his men. He doctored and dosed them with his own hand, and by his elaborate system of magazines he kept them well supplied with biscuits and cheese. At the same time he took care his officers should not grumble. When the day's work was done it was his wont to unbend in frankest good fellowship. Then while his canteen was unpacked it was his delight to sit on the grass beside it and pitch joints of cold meat to his officers, who gathered round. No one could bear the hardships of a campaign better than tough "old George," and no one knew better how to lighten them.
No wonder the work prospered. On June 9th Monk had started, and by the 11th he had established his first advanced magazine at the foot of Loch Tay. Here he received intelligence from Morgan, who was operating from Inverness on the line of the Spey, that Middleton had summoned a rendezvous of the clans at Loch Ness head, anticipating a move from the south. Monk at once turned northward and ordered Morgan on to the line of the lochs, with instructions to close in behind Middleton as soon as he passed over it. Brayne, he knew, had left Ireland a week ago, and between the three columns he felt sure of forcing the Royalists into an engagement. The zeal of the impetuous Morgan spoiled the combination. So rapidly did he move that he fell in with the Royalist vanguard as it emerged from Glengarry and flung it violently back into the hills. The result was that as Monk descended the northern slopes of the Grampians Middleton retreated to Kintail. Still much had been gained. The surprise from Ireland had proved a complete success, and right and left Monk was now able to join hands with Morgan and Brayne along the line of the lochs. Middleton and his friends were thus shut within the northern area, where Monk could renew his combined operations on definite lines. Loch Ness head was now in touch with Inverness by means of a gunboat which had been dragged up into the dock. Here Morgan was established, while the general advanced up Glen Moriston to try and drive his enemy northward or into his lieutenant's arms. In the effort Monk fairly surpassed himself. The country proved more difficult every step he took: the weather was so violent that the cattle could not keep the hills; yet from glen to glen Monk and his red column chased Middleton and his Highland chivalry. Such marching astounded them. At every stride the Southron trod on their heels, and twice they had to abandon stores in order to keep out of his reach. But flesh and blood could not stand such work for long, and at the end of a week Monk retired to reprovision from Inverness, having laid waste the whole of the country from which Middleton was drawing his supplies, and set the "red cock crowing" in the home of every chief who had joined him.