About the close of Gregory's first official year (March, 1074), he assembled a numerous council at Rome, for the purpose of declaring war against the two great vices of the European clergy, and the two great hindrances to his theocratic scheme, namely, concubinage and simony, or the marriage of the priests and the sale of benefices. Many who were favorable to reform thought the edict as to celibacy not only severe but unjust, because it applied equally to the most honorable marriages and the basest profligacy. It was resolved in council, without opposition: first, that priests should not marry; secondly, that those who were married should put away their wives, or renounce the priesthood; thirdly, that for the future no one should be admitted to holy orders who should not profess inviolable continence.
Many of the early fathers had endeavored to establish the connection between celibacy and sanctity, and to persuade men that those who were wedded to the church should avoid the contamination of an earthly union. Several of the popes had also advocated celibacy; but, unless under the severest personal discipline or in the strictest monastic communities, it was little observed and probably never enforced beyond the bounds of Italy. But Gregory made his voice to be heard and feared on this subject from the Vatican to the utmost limits of Latin Christendom. He wrote letters to all archbishops and bishops, princes, potentates, and lay officers of every degree, on pain of incurring severe punishment or eternal perdition, to cast out and depose, without mercy, all married priests and deacons, and to refuse their contaminating ministrations. These despatches were full of anathemas against all who resisted his decrees; and, assuming the place of God, he says, "How shall they obtain pardon for their sins who despise him who openeth and closeth the gates of heaven to whom he pleaseth? Let all such beware how they call down the divine wrath upon their own heads;.... how they incur the apostolic malediction, instead of earning that grace and blessing so abundantly poured out upon them by the blessed Peter! Let them be assured that neither prince nor prelate shall escape the doom of the sinner who shall omit to drive out and expel, with inexorable rigor, all simoniacal and married priests; and all who shall listen to the call of carnal sympathy or affection, or shall from any worldly motive withhold the sword from the shedding of blood in the holy cause of God and His church, or shall stand aloof while these damning heresies are gnawing at the vitals of religion,.... shall be regarded indiscriminately as accomplices of the heretics, as counterfeits and cheats."