Religion

The new ideals of humanism, although more secular in some aspects, developed against a Christian backdrop, especially in the Northern Renaissance. Much, if not most, of the new art was commissioned by or in dedication to the Church. However, the Renaissance had a profound effect on contemporary theology, particularly in the way people perceived the relationship between man and God. Many of the period's foremost theologians were followers of the humanist method, including Erasmus, Zwingli, Thomas More, Martin Luther, and John Calvin.

The Renaissance began in times of religious turmoil. The late Middle Ages saw a period of political intrigue surrounding the Papacy, culminating in the Western Schism, in which three men simultaneously claimed to be true Bishop of Rome. While the schism was resolved by the Council of Constance (1414), the 15th century saw a resulting reform movement known as Conciliarism, which sought to limit the pope's power. Although the papacy eventually emerged supreme in ecclesiastical matters by the Fifth Council of the Lateran (1511), it was dogged by continued accusations of corruption, most famously in the person of Pope Alexander VI, who was accused variously of simony, nepotism and fathering four illegitimate children whilst Pope, whom he married off to gain more power.

Churchmen such as Erasmus and Luther proposed reform to the Church, often based on humanist textual criticism of the New Testament. It was Luther who in October 1517 published the 95 Theses, challenging papal authority and criticizing its perceived corruption, particularly with regard to its sale of indulgences. The 95 Theses led to the Reformation, a break with the Roman Catholic Church that previously claimed hegemony in Western Europe. Humanism and the Renaissance therefore played a direct role in sparking the Reformation, as well as in many other contemporaneous religious debates and conflicts.

In an era following the sack of Rome in 1527 and prevalent with uncertainties in the Catholic Church following the Protestant Reformation, Pope Paul III came to the papal throne (1534–1549), to whom Nicolaus Copernicus dedicated De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres) and who became the grandfather of Alessandro Farnese (cardinal), who had paintings by Titian, Michelangelo, and Raphael, and an important collection of drawings and who commissioned the masterpiece of Giulio Clovio, arguably the last major illuminated manuscript, the Farnese Hours.