Sixteenth-century renaissance artists like Leonardo da Vinci and Michelangelo Buonarotti were able to clearly recreate the three-dimensional physical reality of the human form on two- dimensional surfaces.

One key to their achievement lay in understanding the underlying, hidden structure of the human body. Renaissance artists did this through careful observation of nature, including studies of anatomical dissections, enabling the artist to produce realistic representations of observed objects.  But close observation of the natural world was nothing new, nor unique to renaissance artists.  Medieval artists were also good observers, especially in the period just prior to the Renaissance.

What was new in the fifteenth century, was a corresponding observation of three-dimensional physical space, and the means by which the artists represented that space on a on two- dimensional surface.  This system, called "perspective," produced a greater sense of "realism," and a correspondence between the physical reality of nature and the representional reality created by the artist.  This was all made possible through mathematics.

The process of framing is a central feature of the fourteenth and fifteenth centuries as periods of tremendous transition and as ones of remarkable continuity. If, for example, we examine two chapels in the Dominican church of Santa Maria Novella in Florence, their stylistic differences are immediately obvious. The first chapel, painted by two brothers, Andrea (active, 1343-68) and Nardo di Cione (d. 1365/6), in the late 1350s, has images of damnation and salvation with a dramatic altarpiece dominated by the stiff, frontal figure of Christ passing down Christian law and doctrine to Sts Peter and Thomas Aquinas. The second chapel, painted almost a century and a half later by Filippino Lippi (1457- 1504), is equal in scale but has reduced the importance of the altarpiece, and concentrated the narrative on single-frame scenes of apostolic miracles. The early Christian story illustrating the victory of St Philip over a demon is set against a triumphal arch and sits securely within all'antlca grotesque masques and ornaments which jostle for the viewer's attention. The spatial illusion is convincing, the dramatic gestures evocative, and the naturalism is cleverly mixed with antique allusions.

But however dramatic the changes in style, the similarities also deserve our attention. Despite the distance in time, both chapels were commissioned by members of the same renowned Florentine dynasty, the Strozzi. They served the same purpose, acting as burial spots, sites of memorialization where masses and prayers for the dead could be provided. Both patrons, Tommaso Strozzi in 1357 and Filippo Strozzi in 1487, insisted on drawing up contracts with their painters specifying the quality of the materials, the time the work would take, and the final cost. Even the technique employed, true fresco in tempera paint with ultramarine blue and gilding laid on, was the same. Finally, the stories they told, of the Last Judgement and of the saints, were drawn from the same Christian tradition.

Thus any story of art which focuses on the appearance and development of a single visual style, such as the reuse and adaptation of classical motifs and of linear perspective, has limitations as well as advantages