Overton's former misunderstanding with the Protector having been made up, he had been sent back to Scotland, as we saw, in September, 1654, to be Major-General there under Monk, and pledged to be faithful in his trust until he should himself give the Protector notice of his desire to withdraw from it. For a month or two, accordingly, all had gone well, Monk in the main charge of Scotland, with his head-quarters at Dalkeith, near Edinburgh, and Overton in special charge of the North of Scotland, with his head-quarters at Aberdeen. Meanwhile, as Oliver's First Parliament had been incessantly opposing him, questioning his Protectorship, and labouring to subvert it, the anti-Oliverian temper had again been strongly roused throughout the country, and not least among the officers and soldiers of the army in Scotland. There had been meetings and consultations among them, and secret correspondence with scattered Republicans in England and with some of the Parliamentary Oppositionists, till at length, if Thurloe's informations were true, the design was nothing less than to depose Monk, put Overton in supreme command, and march into England under an anti-Oliverian banner. The Levellers, on the one side, and the Royalists, on the other, were to be drawn into the movement, if indeed there had not been actual communications already with agents of Charles II. It may be a question how far Overton himself was a party to the design; but it is certain that he had relapsed into his former anti-Oliverian humour, and was very uneasy in his post at Aberdeen. "I bless the Lord," he writes mysteriously from that town, Dec. 26, in answer to a letter of condolence from some friend—"I bless the Lord I do remember you and yours (by whom I am much remembered) so far as I am able in everything. I know right well you and others do it much for me; and, pray, dear Sir, do it still. Heave me up upon the wings of your prayers to Him who is a God hearing prayers and granting requests. Entreat Him to enable me to stand to his Truth; which I shall not do if He deject or forsake me." This letter, as well as several letters to Overton, had been intercepted by Monk's vigilance; and hardly had it been written when Overton was arrested by Monk's orders, and brought to Leith. At Leith his papers were searched, and there was found in his letter-case this copy of verses in his own hand:—
"A Protector! What's that? 'Tis a stately thing
That confesseth itself but the ape of a King;
A tragical Cæsar acted by a clown,
Or a brass farthing stamped with a kind of crown;
A bauble that shines, a loud cry without wool;
Not Perillus nor Phalaris, but the bull;
The echo of Monarchy till it come;
The butt-end of a barrel in the shape of a drum;
A counterfeit piece that woodenly shows;