The Roman Catholic Church's decline during the Reformation was clearly not caused by a single event or action. Indeed, numerous self-inflicted and externally inflicted wounds were imposed in the Church. Self-inflicted wounds hurting the Church included the decline in papal credibility and ill will amongst clerical authority. The latter of these two wounds entailed regional biases among nearly every the archdiocese leading to a Great Schism in the Church. The externally inflicted wounds all had more to do with increased educational opportunities spread throughout the Papacy's "jurisdiction". These obviously meant that modernities in thought, giving rise to theological and philosophical examinations of the church by its subjects, would question the church's authority. And with the Church's authority now being simultaneously doubted in these two realms, one could virtually predict the "Reformation" to follow.
The Papacy, in the beginning of the Reformation, was an utter disgrace. Pope Celestine V resigned because he felt the papacy's duties were compelled to be carried out in an intolerable and ungodly manner; threatening his soul.
Pope Boniface VIII was kidnapped and defiled by the Spanish king, and shamefully died soon thereafter. Later, the Avignon Papacy - in which the Papacy was in France - and Great Schism - in which numerous, feuding Popes served concurrently - ensued. [Book p. 364-7]
Surprisingly, the majority of conflicts arising from this lay not in the incredibility of the Church itself, but rather of Church practices. The traditional medieval thought of piety through the sacraments and extensive oral prayer were castigated by some who saw godliness as a more personal, inner feeling. A near-perfect exemplification of this "new piety" is mysticism, which involves a spiritual union with G-d through extensive reflection. Philosophically, many people deviating from the church were simply in disagreement with church logic. John Calvin, who is...