During the winter the Independent party, who were in earnest about crushing the king's power, and many of whom were inclined to believe that the only means of reaching a permanent settlement lay in deposing him, gained the upper hand in the House of Commons. They saw the necessity of organising an army the soldiers of which should be permanently enlisted and brought under thorough discipline, on the model in fact of Cromwell's regiments. They saw also the necessity of removing from the command men like Manchester, and even Essex, who were almost as much afraid of victory which should destroy the king, as of defeat which should leave him absolute. As a means to this end they proposed the Self-denying Ordinance, which disqualified all members of both houses from holding military commands; but the Lords rejected it. The latter however agreed to the scheme for a New Model army, to consist of 21,000 men regularly paid out of the taxes, and therefore dependent on no mere local resources, to be commanded by the younger Fairfax. Having done so they passed a new Self-denying Ordinance, which merely required that members of both houses should resign the posts they held, but contained no proviso against re-appointment. It is plain that the Lords were actuated by motives partly selfish, partly political: they desired if possible to retain control over the armies. But the result of their action was to make possible the retention of Cromwell's invaluable services; he, on the contrary, out of zeal for the cause, had inspired the first proposal, which would have compelled him to retire. The organisation of the New Model was none too rapidly completed; but when it did take the field it proved irresistible.
The need of the Parliament was all the greater because for the campaign of 1645 their Scottish auxiliaries were practically not available. Late in the previous summer Montrose had succeeded in inducing a great part of the Highlands to take up arms for the king, and in a series of short campaigns, continued contrary to the usual practice of that age through the winter, had inflicted so many blows on the king's enemies all over Scotland that Leven's army was much wanted at home. Rupert, who was in the Severn region, urged his uncle to join him with all available troops, and make a push northwards, so as to defeat or drive away Leven's much diminished forces, and restore the royalist cause in the north of England, before the New Model army was ready. But for a brilliant dash made by Cromwell, who at the head of 1500 cavalry swept right round Oxford, defeating one detachment after another, and clearing the neighbourhood of all draught horses, there might have been time to achieve much. The delay thus caused prevented Charles from taking the field for some little time: but the Parliament went far towards neutralising this advantage by instructing Fairfax to go into Somerset and relieve Taunton, the most strongly Puritan town of the west, which was in great straits. Hearing that the king had called to Oxford some of the royalist troops in the west, they recalled Fairfax, too late to prevent the king marching where he pleased. They followed up this waste of time, which was not altogether their fault, by the error of bidding Fairfax besiege Oxford, where the king was not: it ought to have been sufficiently plain that to defeat the king's army in the field was the one paramount object. The king however, instead of either going northwards in earnest, which might have achieved something, or gathering every available man to face Fairfax, which would at any rate have brought matters boldly to a crisis, pushed across to Leicester, which he stormed after a few days' siege. Here he heard that Oxford was badly straitened for provisions, and must surrender unless soon relieved. Nothing can more strongly mark the incompetence of the king and his officers to administer, however they might fight, than his having left his head-quarters on a vague campaign, without having satisfied himself that the city was adequately provisioned to stand the siege which he knew was impending. There was nothing for it but to turn back towards Oxford. At Daventry the king learned that Fairfax had abandoned the siege; and he accordingly halted, not venturing to go northwards again until he knew that Oxford was properly supplied.
On the news of the storm of Leicester, the Parliament bade Fairfax take the field against the king, and at the same time acceded to the unanimous request of Fairfax's officers that Cromwell might be appointed to the vacant post of lieutenant-general. Such was the presumptuous contempt of the royalists for the New Model, that they allowed Fairfax to approach within a dozen miles of Daventry before they heard that he was moving towards them at all. They then withdrew a little further north to Market Harborough, but on Fairfax pressing on they saw that a battle was inevitable, and returned southwards to meet him.
The battle of Naseby merits but little description; it was Marston Moor over again, only with the superiority of numbers greatly on the parliamentary side; and therefore victory was much more easily won. Fairfax drew up his army behind the crest of a line of hills, so that the enemy could not see their numbers till he was committed to an attack. As usual the infantry was in the centre, with Skippon at their head; Cromwell commanded the cavalry on the right wing, Ireton on the left. The royalist infantry was under Sir Jacob Astley, Rupert on the right wing, Langdale on the left, Charles himself headed a small reserve. Fairfax numbered less than 14,000 men, but even so he had nearly double the king's strength. As in all the battles of the war where the ground did not absolutely prevent it, there was a direct attack all along the line, the royalists having the disadvantage of advancing up-hill. The infantry engaged in a fierce struggle, which remained doubtful till the cavalry intervened. Ireton was somewhat hampered by the roughness of the ground, and a great part of his wing was defeated by Rupert's charge and pursued off the field. It seems scarcely credible that Rupert should have been so feather-brained, after repeated experience: but he galloped as far as Naseby village, a mile and more in rear, and would have plundered Fairfax's baggage had not the guard fired on him. Then he awoke to his duty, and returned to the field, but even in that short time the battle was over. Cromwell had had no real trouble in overthrowing the weaker royalist cavalry opposed to him; as they bore down upon the reserve, followed hard by part of Cromwell's force, the king ordered his reserve cavalry to charge the pursuers, and rode forward to place himself at their head. As he did so, one of his suite seized his bridle, and turned his horse round, exclaiming "Will you go upon your death?" It was the best thing Charles could have done, for his own fame and for the cause he represented. He yielded however, and the reserve retreated a little way, and then halted again to await the inevitable. Cromwell, and the unbroken parts of Ireton's wing, were meanwhile charging into the flanks and rear of the royalist infantry. Many surrendered, the rest were cut to pieces: the king's infantry ceased to exist. When Rupert had by a circuit regained the king, there was nothing left but to escape. The king's baggage fell into the hands of the victors, including all his correspondence. The Parliament with excellent judgment instantly published a selection of the letters, under the title of "The King's Cabinet Opened," which did more harm to his cause than the loss of the battle of Naseby. The one unpardonable offence in the eyes of Englishmen has ever been the bringing in of foreigners to interfere in their affairs. And Charles was convicted out of his own mouth of incessant intrigues to get help not only from Irish and Scottish Celts, who though fellow-subjects were detested as semi-savages, but from France, Holland, Lorraine, from any one who could be importuned or bribed (with promises only) to send him aid.
The king with his usual optimism thought all could yet be put right: even the total overthrow of Montrose two or three months later did not impress him. The war was however virtually decided at Naseby, though all hostilities had not quite terminated a year later. The New Model army made short work with the royalists in Somersetshire; the last force which the king had in the open field was crushed at Stow on the Wold; castle after castle surrendered. The king presently shut himself up in Oxford, whence in the spring of 1646 he stole across England and took refuge in the camp of the Scots, to their extreme discomfiture. After an interval the Scots yielded up the king on the demand of the English Parliament. Many months elapsed, filled with negotiations for the restoration of Charles to his throne on terms, negotiations rendered abortive partly by the antagonism between Independents and Presbyterians, mainly by the king's own incurable inability to look facts in the face, or to abide by any plan or promise. An attempt of the moderate party in Scotland to restore him to his throne, by an invasion combined with risings of the English royalists, failed disastrously. The Independents held Charles to be guilty of this wanton bloodshed, and forcibly ejecting their opponents from the House of Commons took possession of the government. Their first act was to bring Charles to trial and public execution: their next to declare the monarchy and the House of Lords abolished, and to confide the executive authority to a council chosen by the Commons. This new experiment in politics worked with very fair success, seeing that they had all the world against them outside England, and were only supported in England itself by a comparatively small minority, who however had the enormous advantage of knowing their own minds. Cromwell was sent over to reduce Ireland to submission, which he did effectively. He had hardly completed the task when he was recalled to make war on Scotland, which had declared for Charles II.
On July 22, 1650, Cromwell crossed the Tweed, and marched towards Edinburgh. His old coadjutor at Marston Moor, David Leslie, was in command against him, and by skilful manœuvring in the country round the capital, managed to keep Cromwell at bay for several weeks, without being forced to an engagement. Supplies at length began to fail, and Cromwell reluctantly began a retreat by the coast road as far as Dunbar. If supplies could be brought him thither by sea, which depended on the weather, there being no good harbour, he could still hold his ground: if not he must retire into England. Leslie followed at once, further inland; having the shorter distance to go he succeeded in blocking the roads beyond Dunbar, and encamped on the heights to landward of the town, Cromwell occupying the level ground along the seashore. The Scottish position was unassailable, as Leslie's positions had been in Midlothian: moreover there had been a good deal of sickness in the English army, due chiefly to the wet weather, which had reduced its numbers to little more than half those of the enemy. Unless Leslie made a mistake, Cromwell would have to embark, and confess that he had failed totally. It was reported afterwards that the committee of the Presbyterian Kirk pressed Leslie not to allow Cromwell to escape, and that he in consequence made the disastrous move which led to his defeat. There is however no adequate authority for this, any more than for the well-known anecdote that Cromwell, noting Leslie's false move, exclaimed, "The Lord hath delivered them into our hand:" either would be in keeping, and is therefore all the more likely to have been invented. The one excuse for Leslie's blunder lay in the fact that his army was encamped on bare hills in frightful weather, a state of things which could not be continued indefinitely. Confidence in his superior numbers may easily have led him to believe that he could afford to move down and force Cromwell to fight: possibly a safe way of doing this might have been found, but the movement he actually made exposed him to a fatal blow.
A little stream called the Brocksburn flows along the base of the hills on which Leslie was posted, and then northwards across into the sea, a mile or so east of Dunbar, flowing at the bottom of a little ravine which it has hollowed out for itself. There were but two points where the steep banks of this ravine were broken enough to allow even carts to pass, one close under the hills, which was held by Leslie's outposts, the other a little way out into the plain, where the high-road from Dunbar towards Berwick runs. Cromwell's army lay on the Dunbar side of this stream, which formed something of a defence for his front. If Leslie could occupy the spot where the high-road crosses the Brocksburn, he could compel an action when he pleased, besides more effectually blocking any communication with England. In order however to do this, he drew down his whole army on to the narrow strip of ground between the burn and the base of the steep slope, and then edged his whole line somewhat to the right, so that his right wing, with most part of his cavalry, lay beyond the road. Cromwell coming out of Dunbar to his camp late in the afternoon, saw the movement being completed. He instantly perceived the opportunity it gave him, and pointed it out to Lambert his major-general: "to which he instantly replied that he had thought to have said the same thing to me." The opportunity was much like that which Marlborough saw at Ramillies, and was used with equally decisive effect. If Leslie's right wing were attacked with superior force, it could be overpowered before the rest of the army, cramped in the narrow strip of ground between the Brocksburn and the hill, could move to its support. And Cromwell could bring overwhelming strength to bear in spite of his inferiority of numbers, because the enemy could not cross the burn elsewhere to make a counter attack. Under cover of darkness the English troops could be massed opposite the slope giving access across the burn to the enemy's position.[54] The assault was to have been made at dawn on September 3, but was a little delayed: the enemy were consequently not surprised. "Before our foot could come up, the enemy made a gallant resistance, and there was a very hot dispute at sword's-point between our horse and theirs. Our first foot after that they had discharged their duty (being overpowered with the enemy) received some repulse, which they soon recovered. For my own regiment under the command of lieutenant-colonel Goffe, and my major, White, did come seasonably in; and, at the push of pike, did repel the stoutest regiment the enemy had there, merely with the courage the Lord was pleased to give. Which proved a great amazement to the residue of their foot; this being the first action between the foot. The horse in the meantime did, with a great deal of courage and spirit, beat back all oppositions; charging through the bodies of the enemy's horse and of their foot: who were, after the first repulse given, made by the Lord of Hosts as stubble to their swords."[55] The quality of the English troops was probably superior, and their officers more experienced; they had the impetus of the first rush to help them, and so far as can be judged superior numbers at the critical point. Naturally the struggle, though sharp, was not long. Just as the sun rose over the sea, "I heard Nol say," relates an officer who was in the battle, "in the words of the Psalmist, Let God arise, and let his enemies be scattered." The defeated portion of the Scots fled eastwards, abandoning everything; the rest of Leslie's army, taken in flank, and with hardly any cavalry left, was able to make no resistance. Cromwell reported nearly 10,000 prisoners, and 3000 of the enemy killed, while his own loss was but small. The Scottish army was virtually annihilated.