Superficially regarded, this last exception is suggestive of a commercial monopoly enforced by the threat of spiritual penalties; and so clearly has it been seen that a damaging significance might readily be attached to it, that the accuracy of the passage has frequently been doubted. M. Audin, who in his Histoire de Martin Luther, vol. i. pp. 429-432, gives a copy of the 'Indulgence,' renders the passage thus: 'occasione aluminum (_sic_) sanctæ ecclesiæ,' &c. By using the word sic, and by appending the note 'Tiré d'une source protestante par un protestant,' M. Audin would seem to have intended to suggest not merely that he doubted the correctness of the copy to which he had had access, but also that the apparently objectionable features of the document might be attributable to inaccuracy. But transactions of which the causes are imperfectly understood may give rise to very erroneous opinions; and in this case even the most cursory glance at the state of Europe during the pontificate of Pius II., when the alum-works of Tolfa came into existence, will show that there were grave reasons for treating the importation of alum as a most heinous offence--reasons which might well affect the decrees of the Pope, and which had not lost their importance in the time of Leo X. Until the discovery that alum could be obtained from the hills near Tolfa, the Italians had been dependent for their supplies of this commodity, which they used in very considerable quantities, upon the Turks, who, it is to be borne in mind, had but a few years previously taken Constantinople, and who were now the scourge and dread of Christendom. The Papal view as to the use to which the discovery should be turned is shown in the following extract from a brief of Pius II.:--