The sectaries and their general were meanwhile advancing into Scotland, but in circumstances so difficult that they were more occupied with escaping from their own perils than with taking advantage of the weakness and divisions among their enemies. Everywhere before them, as they marched, they encountered a desert; men and flocks had disappeared in accordance with the orders of Lesley and the passionate exhortations of the Presbyterian ministers. Without any other resource in the country itself, Cromwell could only feed his troops by means of provisions coming to him by sea from England, which compelled him to continually proceed along the coast. Lesley remained behind in his intrenchments, between Edinburgh and Leith. Bad weather engendered a host of diseases in the English army. "They hope," wrote Cromwell to Bradshaw, on the 30th of July, "that we shall famish for want of provisions, which is very likely to be if we are not timely and fully supplied."
The situation had become so urgent that Cromwell resolved to fall back upon Dunbar, in order to wait there for convoys and reinforcements. From there it was possible, if the supplies were too long delayed, to regain the English border. Upon the way, Lesley, having at length issued forth from his camp, constantly harassed the English. Scarcely had they arrived at Dunbar, when they found their retreat cut off by a considerable detachment occupying the defile of Copperspath, "so narrow," said Cromwell himself, "that ten men to hinder are better than forty to make their way." Lesley yielded to the solicitations and anger of the fanatics. He had hitherto carefully avoided battle, being satisfied with driving before him every day the famous Ironsides and their invincible general, without endeavoring to measure his strength with them. But the ministers were eager to enjoy the glory of victory, and called upon the general not to suffer the enemy to escape whom God had delivered into their hands. "They had disposed of us," said Cromwell, "and of their business by sufficient revenge and wrath towards our persons, and had swallowed up the poor interest of England, believing that their army and their king would have marched to London without any interruption." Lesley resisted no longer. "To-morrow, at seven o'clock in the morning," he said, on the 2d of September, to his officers, "the English army will be ours, dead or alive."
At this moment Cromwell was leaving a prayer-meeting, and he mounted on horseback, with Lambert, his major-general. Surveying with his telescope the positions of the Scottish army, he was struck by the movement which was taking place among the enemy. Lesley was preparing to throw himself across his passage with all his troops. Cromwell was only anxious to fight. "The Lord delivers them into our hands; they come!" he exclaimed, and he proposed to his officers to forestall the Scots and marched towards them. Monk vigorously supported the opinion of the general, and solicited the command of the infantry of the advanced guard. The English spent the night in preparing for the struggle.
A dense fog prevailed at daybreak. The first engagements were not fortunate for Cromwell and his troops. The men fought almost without seeing each other, to the cries of "Covenant" among the Scotch, and "The Lord of Hosts" amongst the English. The Scottish lancers threw the English advanced guard into some disorder; towards seven o'clock the regiment of Cromwell charged sharply. At the same time the sun, dispersing the mists, lit up the sea and mountains. "Let God arise," exclaimed Cromwell, "and let His enemies be scattered!" Inspired by his enthusiasm, his soldiers redoubled their efforts; the Scotch cavalry wavered; an infantry corps, which yet resisted, was broken by the Ironsides. "They run! they run!" cried the English. The rout had set in. "They were now but stubble to our swords," wrote Cromwell. At nine o'clock the battle had ceased; three thousand dead bodies and ten thousand prisoners testified to the victory of the English general. Four days later he was master of Leith, of all the country in the neighborhood of Edinburgh and of the latter city itself, with the exception of the Castle. Charles II. and his government were at Perth. Lesley, with the remains of his army, had fallen back upon Stirling. The republican Parliament could sleep in peace. Scotland, being invaded, had no longer anything to do but to defend herself upon her territory.
Scotland, in effect, thought only of defending herself; but her king soon thought of attacking. He endeavored to escape, and place himself at the head of the royalist movements which were promised in the northern districts; but, although he was soon retaken and brought back to Perth, his attempt gave uneasiness to Parliament, that resolved to take a decisive step and solemnly crown the king at Scone, according to the ancient Scottish custom. The ceremony took place on the 1st of January, 1651. Charles, who notwithstanding his grave faults, possessed tact and the art of pleasing, took advantage of the crowd which thronged around him to secure numerous partisans. The moderate party began to regain influence in the councils. Argyle once more found himself in rivalry with the Duke of Hamilton, brother of him who had perished upon the scaffold. The Presbyterians were a prey to the most violent dissensions. The royalist party was re-forming.
Meanwhile, Cromwell, whose skillful management constantly thwarted the projects and manœuvres of the king, fell seriously ill; so seriously, that the Parliament of England sent two physicians to take charge of him, and the general himself thought he was at death's door. At the same moment royalist plots burst forth in England, despite the severity displayed towards the Cavaliers, and the strict surveillance to which they were subjected by Scott, who was entrusted with this care in the name of the Council of State.
The plots miscarried, and the health of Cromwell was re-established; meanwhile the king had gained ground. The army had been reorganized according to his desire, and he had been placed at its head by the Presbyterian Parliament. At length master of his actions, he abruptly announced to his council his intention of raising the camp, still at Stirling, and waging war in England, where his partisans were only waiting for his presence to declare themselves. Many people complained, protested; Argyle declared that he would not take part in such an undertaking, and retired to his castle at Inverary. The king persisted. He issued a proclamation, and, on the morrow, being the 31st of July, 1651, he took the road to Carlisle with an army of about twelve thousand men. David Lesley had been nominated his Lieutenant-General.
Cromwell had, doubtless, foreseen this movement, and had made no great effort to prevent it, and he foresaw at the same time the rage and terror which it was about to cause in London. He immediately wrote to Parliament: "As the enemy is some few days' march before us, I do apprehend that it will trouble some men's thoughts, and may occasion some inconveniences, which I hope we are as deeply sensible of and have been, and I trust shall be as diligent to prevent as any; but as there is a possibility for the enemy to put you to some trouble, we pray you would, with the same courage, grounded upon a confidence in God—wherein you have been supported to the great things God hath used you in hitherto—improve the best you can such forces as you have in readiness, or as may on the sudden be gathered together, to give the enemy some check until we shall be able to reach up to him, which we trust in the Lord we shall do our utmost endeavor in. This will be a hopeful end of your work, in which it's good to wait upon the Lord, upon the earnest of former experiences, and hope of His presence, which only is the life of your cause."