Brunelleschi is famous for two panel paintings illustrating geometric optical linear perspective made in the early 15th century. His biographer, Antonio Manetti, described this famous experiment in which Brunelleschi painted two panels: the first being the Florentine Baptistery as viewed frontally from the western portal of the unfinished cathedral, the other one is the Palazzo Vecchio seen obliquely from its northwest corner. These were not, however, the first paintings with accurate linear perspective, which may be attributed to Ambrogio Lorenzetti (Annunciation, 1344).


The first Baptistery panel was constructed with a hole drilled through the centric vanishing point. Curiously, Brunelleschi intended that it only be observed by the viewer facing the Baptistery, looking through the hole in the panel, from the unpainted backside. As a mirror was moved into and out of view, the observer saw the striking similarity between the actual view of the Baptistery, and the reflected view of the painted Baptistery image. Brunelleschi wanted his new perspective “realism” to be tested not by comparing the painted image to the actual Baptistery but to its reflection in a mirror according to the Euclidean laws of geometric optics. This feat showed artists vividly how they might paint their images, not merely as flat two-dimensional shapes, but looking more like three-dimensional structures, just as mirrors reflect them. Unfortunately, both panels have since been lost.

Around this time linear perspective, as a novel artistic tool, spread not only in Italy but throughout Western Europe. It quickly became, and remains, standard studio practice.Linear