This memorable declaration was not without effect. On August 13, the Pope earnestly impressed Edward with the duty of keeping on good terms with Bruce. And on August 18, he wrote that, on the prayer of Bruce by his envoys, Sir Edward de Mambuisson and Sir Adam de Gordon, he had granted suspension of the personal citation and of the publication of the sentences till the 1st of April next year. CHAPTER XII PEACE AT THE SWORD'S POINT The Scots manifesto of April 6, 1320, presented a united and firm front to English pretensions and Papal intrigues. Yet there were traitors in the camp. Little more than four months had elapsed when the Black Parliament, held at Scone on August 20, was investigating a conspiracy to kill King Robert and elevate to the throne Sir William de Soulis. Sir William was a brother of Sir John, and a grandson of Sir Nicholas, one of the Competitors in 1292. Edward's emissaries had been tampering with the fidelity of King Robert's barons. The plot still remains involved in obscurity. It was discovered to the King, Barbour heard, by a lady. Gray, however, as well as John of Tynmouth, states that the informant was Sir Murdoch de Menteith, who had come over to Bruce in 1316-17, and remained on the Scots side till his death some sixteen years later; but, apart from his name, there seems no reason to suppose that he was in Edward's pay. Sir William was arrested at Berwick, with 360 squires in his livery (says Barbour), to say nothing of 'joly' knights. He openly confessed his guilt, and was interned for life in Dumbarton Castle. The Countess of Strathearn was also imprisoned for life. Sir David de Brechin, Sir John de Logie, and Richard Brown a squire, were drawn, hanged, and beheaded. Sir Roger de Mowbray opportunely died; but his body was brought up and condemned to be drawn, hanged, and beheaded--a ghastly sentence considerately remitted by the King. Sir Eustace de Maxwell, Sir Walter de Barclay, Sheriff of Aberdeen, Sir Patrick de Graham, and two squires, Hamelin de Troupe and Eustace de Rattray, were fully acquitted. Soulis, Brechin, Mowbray, Maxwell, and Graham had all attended the Arbroath parliament, and put their seals to the loyal manifesto.