The advent of the Renaissance led to a steady rise in the relative safety of the general population throughout Europe. Mercantile brought exotic resources retrieved by explorers, such as silk, spices and tea, leading to an economic boon that essentially began the middle class, neither peasant nor nobility. This growing merchant economy and the rapid expansion of science and technology created more jobs, a wider variety of career paths, and an explosion of literacy across the continent after the invention of the printing press by Gutenberg around 1400. Customization was made available in the lives of the common people; rather than one outfit, the same material as all other peasants, one could have several, each based on one's personal preferences and style. The individual became the new center of society and life itself, fitting the world to himself.
Having already experienced the deep loss of faith and hope in feudal government and the Catholic Church, nobility was no longer enough in and of itself to possess leadership - politics became the new standard. Replacing the standard of hereditary birth with the combination of new wealth and political requirements, Renaissance leadership developed into a widespread European aristocracy. Castle-centered fiefdoms were slowly replaced with towns governed by politicians and businessmen. As firearm technology developed, expensive and well-trained knights were no longer needed, replaced by conscripted mass forces of commoners with little training or expense to the politicians. Although many remnants of the Middle Ages remained through the Renaissance, in the minds of the people, "medieval" died in the Plague.
With the decline of feudalism, countries once defined by their heritage and ruler became defined by the qualities valued by the common people - ethnicity, national identity, wealth, language, military power, etc. This was the beginning of the modern nation-state, the conception of countries as political entities, separated from other nations only by the general values of the people rather than objective and historical differentiation. Monarchs became merely symbols of the nation itself, not truly above or beyond it, and whenever a monarch attempted to possess ultimate power as they had often held in the Middle Ages, rebellion quickly followed. However, this did not stop them from attempting to gain as much power as possible, far surpassing the power of monarchs in the Middle Ages.
As described in Part One, the conversion of Europe to Catholicism was inextricably linked to its cultural reliance on the decision of its leaders. The philosophical advent of self-reliance, life customization and nationalism which developed in the Renaissance also influenced religion. While in the Middle Ages common people valued sacramental religion, heritage, and living the "heaven on earth" of Catholic Mass in every part of their lives with order and regularity, Renaissance commoners came to value physical health and security, mental pleasure and happiness, individual identity, power and expression, and a religious sentiment reminiscent of the ancient Jewish Sadducees popular in the time of Christ, viewing morality as a means of making this life easier and more pleasant. God and the afterlife became both more personal and distant in the minds of Renaissance people. Despite their emphasis on physical health, happiness and security, they believed God should be absolutely separate from the world, a Platonic spiritual divinity whose perfection lied precisely in His separation from this world and the activities of man which, people came to believe, were completely beneath God's concern. Our salvation, performed entirely by God, was simply done for His glory, and the pursuits of man ranged from meaningless to actual hindrances to the life of faith, only being relevant to our life here.
Equally, the general populace began associating the Catholic Church with the royalty they resented so much. With these changes in values, the wealth and power of the royalty was both despised and envied, being insurance of physical security and the power to attain happiness. As I have said, the Church was deeply involved with national government, especially to the royalty, and due to variously-motivated tithes over the centuries the Church had accumulated great wealth and political influence in Europe. Though the corruption this caused in the Church was greatly exaggerated, its existence was a popular focus of the general population, associated with their mutual distaste for royalty. The symbolic meaning of the Church's liturgical gold and the wealth freely given to it over time was transformed from a religious symbol to one of pomp and greed, with the corruption present in the Church's human members emphasized and highlighted over all else.
The Protestant Reformation was the culmination of these seeds of doubt that had existed since the Plague. Protestant theologians, though often different in their theology, uniformly professed a rejection of the Church, citing its wealth, splendor and holes of corruption as proof that it was not the same Church Christ founded. Already in the mind of the people, this movement became very popular, even in its different forms. Allowed to place nation over church, to localize parishes into distinct churches themselves, to customize one's beliefs and morality based on personal preference and opinion, and replacing the pope with kings, Protestantism was widely accepted. Catholicism came to represent an antiquated ornamentation, making it completely inaccessible and irrelevant to the common people and accordingly unfair, unjust and immoral. In popular middle class culture, going against the traditions and morals of the Church was a personal sign of maturity and independence, feeling that their actions were justified by the unfairness and corruption they perceived in the Church - thus were clerical celibacy, religious authority, iconography and many other Church teachings rejected increasingly over time.
The vast growth of wealth, political power and religious diversity in the Renaissance led to many subsequent historical developments. The revival of superstition and magic in the Black Plague period led to the witch-hunts of the 16th century, the popularity of alchemy which stunted the growth in academic chemistry pursued during the Middle Ages, and the eventual trend of favoring ancient paganism to Christianity exemplified by modern Wicca and neo-paganism. While opposing aristocratic wealth and Church authority was intended by the general populace to decrease their power and corruption, removing the authoritative conscience and charitable service the Church provided gave permission for national leaders to pursue power to the furthest extent they could. Unfortunately, even many in the Church, including popes and cardinals, gave in to this temptation, becoming corrupt and providing a negative example which partially inspired the Protestant movement.
While many negative developments occurred because of the Black Plague and Renaissance, many good things also came about, both in the Catholic Church and secular society. Opposing the Reformation gave unity of doctrine and purpose to the Church, purified its conscience, illuminated its theology, and encouraged acts of charity and self-sacrifice that has been a beacon of inspiration ever since, most exemplified by the English martyrs who were murdered by the English government after King Henry VIII's creation of Anglicanism. Although the Church had been studying, preserving and promulgating Greek and Roman knowledge for a millennium by the time of the Renaissance, focusing on it once again reminded Catholics of their Roman character, especially the Church Fathers and the ideal of civilization. Art, science and democracy flourished, largely from Catholic funding and the innovation of groups such as the Jesuits, and the general tyranny of feudalism was somewhat mitigated. However, it has had negative consequences which have led to terrors, genocides, mass irreligion and immorality ever since, and the ideas that inspired these events cannot be forgotten - even their subliminal traces in ourselves.
In truth, it was not primarily what the Renaissance added to European culture, but what had been left behind in the wake of the Plague, the abandoned legacy of the Middle Ages. This created a hole in the spirit of Europe that many have tried to fill with alternative religions, philosophies that proclaim science, politics or economics as the savior of mankind, and simply an indifferent agnosticism that prefers to let the world unfold around them with comfortable neutrality. None have succeeded, and as long as Europe and all its Western-influenced progeny across the globe continue in futility to replace the universal faith, hope and charity of the Catholic Church, the horrors of the 20th century - even that perpetrated in the privacy of a doctor's office - will continue.