How Serious was the Reformation?

The Church of Rome took it pretty seriously (and they knew exactly what they were refuting):  

CANON XI.-If any one saith, that men are justified, either by the sole imputation of the justice of Christ, or by the sole remission of sins, to the exclusion of the grace and the charity which is poured forth in their hearts by the Holy Ghost, and is inherent in them; or even that the grace, whereby we are justified, is only the favour of God; let him be anathema.

CANON XII.-If any one saith, that justifying faith is nothing else but confidence in the divine mercy which remits sins for Christ’s sake; or, that this confidence alone is that whereby we are justified; let him be anathema.

CANON XIII.-If any one saith, that it is necessary for every one, for the obtaining the remission of sins, that he believe for certain, and without any wavering arising from his own infirmity and disposition, that his sins are forgiven him; let him be anathema.

CANON XIV.-If any one saith, that man is truly absolved from his sins and justified, because that he assuredly believed himself absolved and justified; or, that no one is truly justified but he who believes himself justified; and that, by this faith alone, absolution and justification are effected; let him be anathema. .

CANON XXX.-If any one saith, that, after the grace of Justification has been received, to every penitent sinner the guilt is remitted, and the debt of eternal punishment is blotted out in such wise, that there remains not any debt of temporal punishment to be discharged either in this world, or in the next in Purgatory, before the entrance to the kingdom of heaven can be opened (to him); let him be anathema.


(Council of Trent, Decree on Justification)