Whilst the heads of the Protestant party were corresponding with England, the Queen-Regent, on her side, had also been preparing for the struggle which she was now determined to force on, though in order to gain time, she had not discouraged the negotiations entered upon with a view to a peaceable settlement. In answer to her appeals for assistance, the French Court sent her a body of troops, to oppose the forces which the Lords of the Congregation were raising. About the middle of August 1559, a thousand men, under the command of an officer named Octavian, landed at Leith, which they at once began to fortify. Protests and proclamations on the part of the Lords having failed to prevent the operations of the French from being actively carried on, under the eyes of the Regent herself, Leith was invested by the forces of the Congregation.

Sir William Kirkcaldy was one of the military leaders on whose skill and experience the party mainly relied. It is scarcely possible to determine with what official rank he was invested; but there is not wanting evidence to show that, whether by actual appointment, or by virtue of his zeal and of his valour, he stood in a position of considerable importance. When Maitland of Lethington, Secretary to the Queen-Regent, ‘perceiving himself to be suspected as one that favoured the Congregation, and to stand in danger of his life if he should remain at Leith, because he spared not to utter his mind in controversies of religion,’ determined to join the Protestant party, it was to Sir William Kirkcaldy that he surrendered. Such indeed, was his recognised influence with his associates, that, as Throckmorton informed Cecil, the Regent ‘weighed him more than a great many of the rest,’ and made strenuous, but vain efforts to gain him over to her side.

Of Sir William’s personal exploits, the records are only casual and incidental; but they invariably bear testimony to the dashing courage which had won distinction for him in foreign wars. It was conspicuously displayed in one of the most important engagements between the opposing forces. On the 5th of November, a body of French troops was sent from Leith to intercept a convoy of provisions intended for Edinburgh. Arran and Lord James, being ‘more forward than circumspect’ in their attempt to drive them back, allowed themselves to be hemmed in, and forced into a ‘very narrow corner,’ between the low-lying swamp near Restalrig, and the wall that enclosed the park of Holyrood. But for the Laird of Grange and Alexander Whitelaw, who rode up at the head of a few horsemen, and who succeeded in keeping the enemy in check for a time, the whole escort would have been surrounded, and either killed or taken. Even as it was, the loss was serious; and, together with the capture of the expected provisions, led to the abandonment of Edinburgh, which was at once occupied by the French. Kirkcaldy, who had been in the front of the fight, was in the rear of the retreat; and, according to Killegrew’s report of the event to Queen Elizabeth, he only ‘very narrowly escaped over the walls.’

Another of Kirkcaldy’s sallies from the camp before Leith is narrated in a dispatch to Cecil by Sir Henry Percy, who also took part in it—for this was in April 1560; and by that time Elizabeth had at length sent a small contingent of troops to reinforce the army of the Congregation. Dunbar being but a short distance from Leith, and on the highroad to Berwick, it frequently happened that messengers and straggling parties, on their way from the camp to the English Border, were intercepted by pickets from the garrison. To check this, and to teach the French caution, Lord Grey and Sir William devised a stratagem. The latter, with Sir Henry Percy and three hundred troopers, left the camp at dead of night and took up a carefully chosen position, about half a mile from Dunbar. Next morning, at nine o’clock, when there was every probability of detection, a detachment of a dozen men was sent forward as though for the purpose of riding to Berwick. As soon as they were perceived, Captain Hayes, with an equal number of cavalry, started in pursuit, whilst Captain Perrot, at the head of fifty footmen, also marched out so as to be at hand to reinforce him, if necessary. Feigning to be taken at unawares, the decoys turned and made for the camp, managing their flight in such a manner as to lead the pursuers into the ambush. Grange made no attempt to meet the enemy; but as soon as they had all passed by, he rode out with his three hundred men, and cut off their retreat. Charging the French before they had time fully to realise their position, he overwhelmed them and took most of the footmen prisoners. The cavalry were able to take refuge in the neighbouring mansion of Innerwick, but a very brief siege obliged them to surrender also; and Kirkcaldy returned to the camp after having killed thirteen of the enemy and captured forty-five, including the two leaders, Hayes and Perrot, and without having suffered any loss himself.

On the eve of the last but still unsuccessful assault made against Leith, on the 7th of May 1560, by the combined forces of the Congregation and of England, it was Sir William Kirkcaldy who, with Sir Ralph Sadler and Crofts, went forward to examine the breach which the besieging artillery had made in the works. Had his advice been followed, the next day’s failure would have been avoided, for he reported that the attack ought not yet to be made. But, either owing to a misunderstanding or, as was commonly reported subsequently, to treason on the part of Crofts, who was instructed to communicate Kirkcaldy’s opinion to Grey, the assault took place, and was repulsed with heavy loss to the besiegers.

Whilst the siege of Leith was going on, the skirmishing was not confined to the southern side of the Forth. Crossing to the other shore, the French established themselves at Kinghorn and, sallying forth, laid waste all the adjoining country, sparing neither Papist nor Protestant, and even pillaging the estates of their own confederates. Amongst the chief sufferers from their depredations and wanton destruction of property, was Sir William Kirkcaldy, whose house was deliberately blown up. Next day he sent a characteristic message to the French leader, d’Oysel. He told him that, up to that hour, he had acted considerately towards the French, and saved their lives when he might have allowed their throats to be cut. But he warned him not to expect such treatment for the future. ‘As for Monsieur d’Oysel,’ reports the chronicler, ‘he bade say to him, he knew he would not get him to skirmish with, because he knew he was but a coward. But it might be he should requite him in full, either in Scotland or in France.’

The French soon learnt to their cost that Kirkcaldy had not been indulging in mere braggart threats. At the head of a thousand horse, and accompanied by the Master of Sinclair, he lay in wait for them day and night, and made it unsafe for them to venture out of Kinghorn except in large bodies. One of his exploits was the capture of three ships, laden with victuals, and the slaughter of some sixty Frenchmen that were on board. Another, of which the details have been recorded, resulted in the death of the French Captain, L’Abast, and of forty or fifty of his men. L’Abast having sallied out from Kinghorn, was plundering as usual, sparing ‘neither sheep, oxen, kye, nor horse.’ When he and his men got sufficiently far inland to make it impossible for reinforcements to come to them from the main body, Grange, who had been following their movements, charged down upon them with a company of his horsemen. The French beat a hasty retreat as far as Glennis House, into which they threw themselves. Whilst some occupied the mansion, others took up their position within the courtyard. The assailants were at considerable disadvantage, for they were armed with spears only; and their horses were useless to them in an attack against men posted behind stone walls. The French, on the contrary, all had arquebuses. Undeterred by the odds against him, Kirkcaldy ordered his men to dismount, and led them to the assault. As they advanced, they were met with a sharp fire that injured several of them, amongst others, Sir William’s brother, David. There was one critical moment of hesitation, which would probably have been followed by a disordered and disastrous retreat but for the courage of the Scottish leader. ‘Fie!’ he cried to his men, ‘Let us never live after this day, if it is to be said we recoiled before French skybalds!’ Then, rushing forward with the Master of Sinclair, and followed by others whom his words had roused, he succeeded in forcing his way into the courtyard. The death of L’Abast, who, though borne down by the impetuous inrush, refused to ask for quarter, threw the French into confusion. Few of those outside the house escaped the fierce slaughter that followed; whilst those within it were glad to surrender at discretion. From that day, as the chronicler drily remarks, ‘the French were more circumspect in straying abroad.’

At Tullybodie, too, there was some sharp fighting for the possession of the bridge. But, though Kirkcaldy succeeded in cutting it down, the check to the advance of the French was only temporary. They retired to Doune, where they crossed the river by means of a bridge, which they built of timber torn from the roof of the parish church.

Kirkcaldy and Sinclair did not carry on this harassing mode of warfare without considerable danger to themselves. On one occasion the Master had his horse slain under him, and barely got off with his life. On another, Grange was nearly captured in his own house at Halyards. Referring to these narrow escapes, Maitland of Lethington bears testimony to the estimation in which the two dashing leaders were held, and to the value set on their services by the Lords of the Congregation. ‘If at this time they should have lost the said two men,’ he wrote, ‘it would have been to them more hurt than to the Frenchmen to have lost a thousand soldiers; it would have been more skaith than to have had all the Frenchmen in Scotland slain.’ John Knox, in a letter to Mrs Anna Locke, also makes admiring and grateful mention of Kirkcaldy’s achievements. ‘God will recompense him I doubt not,’ he says; ‘for in this cause and since the beginning of this last trouble specially, he hath behaved himself so boldly, as never man of our nation hath deserved more praise. He hath been in many dangers, and yet God hath delivered him above man’s expectation. He was shot at Lundie, right under the left pap, through the jack, doublet, and sark, and the bullet did sticke in one of his ribs. Mr Whitelaw hath gotten a fall, by the which he is unable to bear armour. But, God be praised, both their lives be saved.’

Whether Kirkcaldy was actually wounded, however, seems rather doubtful. That, if he was, his hurt cannot have been serious, may be gathered, not only from the fact that no interruption of his activity at this time is recorded, but also from the following passage, which occurs in one of Sadler’s letters to Crofts: ‘Kirkcaldy hath no such hurt as we wrote of, which arose of another Scottishman that was indeed hurt in the same sort as we did write; and before that Kirkcaldy slew a Frenchman, whereby the Protestants had the first blood, which they do take for good luck.’

By the beginning of 1560, both contending parties had grown tired of the desultory, and practically useless fighting which had now been going on for months. Negotiations had again been entered upon with a view to the cessation of hostilities, when, on the 10th of June, the death of the Queen-Regent took place. Although there is reason to believe that this time she was really sincere in her wish for peace, it is probable that her demise accelerated rather than retarded the conclusion of the treaty. That it secured for the Protestant party more favourable terms than she herself would readily have granted, scarcely admits of a doubt.