The term Renaissance was used for the first time by Vasari in his Lives (1550) and refers to the period between the end of the fourteenth century and the second half of the sixteenth, which was characterised by the reflowering or rebirth of culture and art. The whole of Europe was affected by this revival but its roots were indisputably in early Florentine humanism. The rediscovery of classical texts, in an autonomous, secular context, made it possible to affirm man and his freedom of thought and action through critical analysis of the world, following the guidelines of the ancient masters. In every field of thought and action, it meant liberation from the rigid theological dogmas, shackles and fetters of the Middle Ages.
The philosophy of the Renaissance was essentially naturalism, that is, the study of man and the cosmos without reference to metaphysics. Man was the centre of being and the measure of all things, the elected author in whom the harmony between macrocosm and microcosm is re-echoed. Niccolò Cusano, Marsilio Ficino, Giovanni Pico della Mirandola and Giordano Bruno studied Plato and each of them, in his own way, found there the basis for placing man in relation to his capacity for knowledge (Neoplatonism). In science, there was an analogous liberation from the rigid restrictions of metaphysics and the foundations were laid for devising mathematical and experimental methods. A new category of scientist-engineer developed of which Leonardo was the most illustrious. It is not by chance that the image which became the metaphor for Renaissance man in the collective imagination is the "divine proportion", the symbolic representation of man as the measure of all things and which Leonardo took from Vitruvius.
The idea that suggests and then makes man the centre of everything is the most immediate and the one that we accept immediately, but the reference, starting with the name, to the harmony of proportion, makes man divine, in contrast with the image of Gothic man as suffering and deformed. New sciences, such as astrology, alchemy and magic, with their appeal for direct observation of nature, led to the rejection of the old Aristotelian method, based on deduction only. Particular progress was made in astronomy by Copernicus, Tycho Brahe and Kepler, opening the way to Galileo and heliocentrism. In literature, the initial revival by Petrarch and Boccaccio was continued by Alberti, Pulci, Boiardo and Lorenzo the Magnificent and by Poliziano, Machiavelli and Guicciardini.
In art, the Renaissance readopted classical ideals and forms, after the break in the Middle Ages, forming an ideal cultural continuity with the classical world. In Florence, in the course of a few years, an architect (Brunelleschi), sculptor (Donatello) and painter (Masaccio) started a revolutionary transformation of the concept and functions of artistic creativity. Art was no longer a "mechanical" process, that is to say, the skill of a craftsman, but an activity liberalis, in other words, intellectual. Art became the instrument of knowledge and study of reality, a true science with rational, theoretical foundations, such as the laws of perspective. This new foundation of art, through the patronage of the upper classes, spread and developed, reaching the heights of Bramante, Raphael, Michelangelo and Leonardo, as "classicism".