At the heart of the Reformation, another attitude towards salvation
It is not possible here to sketch out the reformers' theology be they Martin Luther[1] in Germany, Ulrich Zwingli[2] in Zurich or John Calvin[3] in Geneva, ... not to mention the odd dozens of lesser known figures who played an equally significant role. However two salient points need mentioning which would result in a massive loss of interest in devotional images and which would, in a great many cases, lead to the campaigns of image destruction.
The first point is nothing less than the storm set off by Luther when he censured, as early as the year 1517, the belief in a salvation achievable through the performance of good works. One of the Reformation's mantras would indeed reiterate that people are justified not by what they do (good deeds, alms, donations to the church etc.) but solely by God's gratuitous intervention on behalf of the believer (this is what theologians mean by the formula “justification by faith”). According to Luther, it is not because such and such a person does good works that they are justified but on the contrary because God has justified them that they can, as a result, do good works. The impact of this reversal was far reaching. In respect of images, it was critical: the funding of devotional images – the very type of good work meant to help obtain the sponsor's salvation was roundly condemned; pilgrimages to pray to relics and images was dismissed; the prayer said before the image of a saint and to his intention was henceforward bereft of any sense.
The second fundamental point is to be found in the admonishments Luther, then other Reformers addressed to the established Church institutions (the Pope in Rome, his bishops and clergy). Secondary to the concept of faith and good works though it be, this opprobrium is no less virulent for all that. The churches born of the reformation held for null and void all the juridical prescriptions from the Church of Rome and they rejected, along with Roman power all its ecclesial system's symbolisms. Turning on the Roman Church was thus also turning against lavishness in places of worship, and specifically devotional images.
And so it was that, all over Europe, the Reformation was very quickly attended by a range of manifestations of image destruction, which are generally known as iconoclastic outbreaks.