The result was that he immediately became involved in a serious quarrel with the Emperor, who realizing how dangerous a rival to his own power had been created by the events just recounted, reasserted his claims to Gelderland even more strongly than before. In looking for allies against Charles, Duke William naturally turned to the Elector of Saxony, whose rights to Juliers and Berg, once rudely revoked by Maximilian, had not been forgotten, but who seems to have preserved sufficiently friendly relations with the family in favour of which his claims had been set aside, to marry Sibylla, one of the sisters of the Duke[615]. Common enmity to Charles V. now drew them very close together, and at the Imperial Court it was actually thought that Cleves had been formally admitted to the Schmalkaldic League[616]. This however was a mistake. Though Duke William was certainly not opposed to the Lutheran doctrines, he had not as yet made open confession of the Protestant faith; and for that reason the Elector and the Landgrave had steadily refused to make a political alliance with him[617]. Still he was on very intimate terms with John Frederic, who had promised, when he wedded Sibylla of Cleves, to advance money for the marriage of her sisters, and thus had a certain right to be consulted when husbands were to be chosen for them. Henry was doubtless well aware of all this, and it was consequently at the Saxon Court that Mont was instructed to obtain information about the Duke of Cleves, and if possible to pave the way for the two matrimonial alliances from which Cromwell hoped so much.