He identified the Papal {18} Church with the Babylonian harlot in the book of the Revelation, and concluded by demanding the most thorough investigation of all the statements which he had made, and the most minute examination of the authorities whom he had cited. This discourse was listened to by a large assembly, among whom was John Major, his old Glasgow principal, and it produced a great effect upon all. Some said, "Others lopped off the branches of the papistry, but he strikes at the root to destroy the whole." Others predicted that he would meet the fate of Wishart, who had never spoken quite so plainly as Knox had done that day. The new archbishop of St. Andrews, not yet consecrated to his office, expostulated with the vicar-general of the diocese for allowing such heretical doctrines to be promulgated without opposition, and that led to the calling of a convention of the learned men of the abbey and the university, before which Rough and Knox were summoned to make answer to nine articles, involving heresies, which had been drawn from their sermons. But nothing more serious resulted from that meeting than a debate between Knox and a friar named Arbuckle, whose arguments Knox easily refuted, and that too with a considerable mixture of the grim humour which ever and anon laughs outright in the pages of his history. Clearly, therefore, it would be a perilous thing for the Church to let such a man do all the preaching to the people; and so orders were issued that each of the learned men in the abbey and university should preach {19} in his own turn on the Sundays in the parish church. This deprived Knox of the opportunity of addressing the congregation on those days when the greatest numbers were in attendance; but he continued his ministry on the other days of the week, and that with such success that although it lasted in all at this time not more than three months, many of the inhabitants of the town renounced popery, and made confession of the Protestant faith by partaking of the Lord's Supper in the reformed manner, the first occasion on which the ordinance was publicly administered in Scotland after that fashion. Thus the beginning of Knox's work marks a distinct stage in the history of the Scottish Reformation. At first, and under what has been called by Lorimer the Hamilton period, peculiar emphasis was laid upon the truths which were revived in the teaching of Luther; under the Wishart period the doctrine of the sacraments came into prominence, and then first the influence of Switzerland began to be felt by Scotland; but under Knox attention was directed especially to the nature and constitution of the church, and the first sermon which he preached, and of which we have given the barest outline, had already in it "the promise and the potency" of the great work which he was yet to accomplish for his native land.