Thus the fate of the Regensburg Book was no longer doubtful. After Elector John Frederick and Luther had become fully acquainted with its contents, their disinclination was confirmed, and Luther demanded most decidedly that even the articles agreed upon should be rejected. On 5 July the estates rejected the Emperor's efforts for union. They demanded an investigation of the articles agreed upon, and that in case of necessity they should be amended and explained by the Papal legate. Moreover, the Protestants were to be compelled to accept the disputed articles; in case of their refusal a general or national council was to be convoked. Contarini received instructions to announce to the Emperor that all settlement of religious and ecclesiastical questions should be left to the Pope. Thus the whole effort for union was frustrated, even before the Protestant estates declared that they insisted upon their counterproposals in regard to the disputed articles.