During the Renaissance the medieval worldview gave way to new forms of thought, expression, and organization. The Renaissance appeared first in the north-Italian city-states, which emerged as autonomous political units from the weakness of the papacy and Holy Roman Empire. Unlike the rest of Europe, these states were based on commercial and financial power and were ruled by fragile coalitions of feudal aristocracy and rich merchants. As the states were politically unstable, they sought novel solutions to government. These states initially experimented with republicanism, devising theories to justify that form against imperial and papal interference. However, pressures including civil strife, warfare, and reliance on condottieri pushed these republics toward despotism. Florence's republic survived longest, falling to the Medicis in 1480. During the Peace of Lodi, the dominant states pioneered the techniques of modern diplomacy. Society in the city-states was marked by new codes of behavior. From changes in marriage practice emerged a class of prosperous, single, leisured adults who explored nontraditional forms of sexuality. The new merchant class displayed and enhanced their power through patronage of the arts. They also cultivated a secular individualism that, breaking with the medieval outlook, stressed worldly excellence and achievement.

The major intellectual expression of the Renaissance was humanism. Primarily an educational program, humanism emphasized study of the Greco-Roman classics. Unlike medieval scholars, Italian humanists studied the ancients for their own sake, as models of exemplary thought and expression that individuals could use to live fully in the world. Attacking medieval scholasticism, humanists developed a cyclical vision of history and methods of critical historical scholarship. Early civic humanism served the needs of republicanism, but later humanism adapted to despotic rule, replacing the ideal citizen with the ideal courtier. Advice books circulated widely. Among the most important of these was The Prince, in which Machiavelli articulated the first truly modern political theory, one that was thoroughly secular, rational, and realistic. Artists expressed the humanist outlook by returning to classical values and aesthetics. Early Renaissance artists realized the promise the Giotto's art by exploring the possibilities of perspective and techniques for representing the human form as it appeared to the eye. Northern painters of this period stressed precise representation of objects in the world. Later Italian artists-e.g. Leonardo, Michelangelo, and Raphael-worked to reconcile perspective with composition. Venetian painters explored the compositional possibilities of color.

During the fifteenth century the Renaissance spread northward, fostered by increasing prosperity and the development of print. Prosperity encouraged education, and print technology, despite censorship, fueled a vital publishing industry. Northern humanists were decidedly Christian, often using their learning to reform the church and revitalize faith. Important Christian humanists include Erasmus, Montaigne, Rabelais, and More. Northern humanism tended to center on royal courts, particularly in Spain, where Jiménez shaped an authoritarian humanism. Northern humanism also inspired a rich literary tradition, represented by, among others, Cervantes and Shakespeare.

As a movement devoted to the capacities of the individual and realistic engagement with the word, the Renaissance introduced modernity into Western civilization.