Environment.

It was in Italy that the artistic values we associate with the Renaissance first began to appear. These values included a new emphasis on naturalistic depiction, on human proportions and human scale in art, and on the rational presentation of observed spaces. During the fourteenth and early fifteenth centuries artists in Northern Italy, particularly in Tuscany, devoted themselves to problems of perspective. Eventually, they mastered techniques that allowed them to reproduce spaces that appeared to have real depth on two-dimensional surfaces. This innovation, known as linear perspective, was not to be perfected until the mid-fifteenth century in the paintings of the Florentine artist Masaccio. Thereafter the humanistically trained artist Leon Battista Alberti codified the methods that Masaccio had used and circulated them in his theoretical treatise On Painting, which he wrote during the 1430s. The breakthroughs that fifteenth-century Italian...