As Henry went on, his "quick and penetrable eyes," as More described them, were more and more opened to the extent of what he could do; and he realised, as he said, how small was the power of the Pope. Papal authority had always depended on moral influence and not on material resources. That moral influence had long been impaired; the sack of Rome in 1527 afforded further demonstration of its impotence; and, when Clement condoned that outrage, and formed a close alliance with the chief offender, the Papacy suffered a blow from which it never recovered. Temporal princes might continue to recognise the Pope's authority, but it was only because they chose, and not because they were compelled so to do; they supported him, not as the divinely commissioned Vicar of Christ, but as a useful instrument in the prosecution of their own and their people's desires. It is called a theological age, but it was also irreligious, and its principal (p. 429) feature was secularisation. National interests had already become the dominant factor in European politics; they were no longer to be made subservient to the behests of the universal Church. The change was tacitly or explicitly recognised everywhere; and _cujus regio, ejus religio_ was the principle upon which German ecclesiastical politics were based at the Peace of Augsburg. It was assumed that each prince could do what he liked in his own country; they might combine to make war on an excommunicate king, but only if war suited their secular policy; and the rivalry between Francis and Charles was so keen, that each set greater store upon Henry's help than upon his destruction.