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.’