Florentine architect and sculptor Filippo Brunelleschi "rediscovered" linear perspective in the early 15th century, while its rules were more fully developed about twenty years later by art theorist Leon Battista Alberti.
Portrait of Brunelleschi
I say “rediscovered”, because before the Early Renaissance the Ancient Greeks and Romans associated the discipline with Euclidean science of optics and indeed practiced it.
With the coming of the Middle Ages and the rising influence of the Church, however, this knowledge was lost, for linear perspective is based on the idea of a single spectator with a single viewpoint - medieval ecclesiastics were affronted by the concept of thus placing Man at the center of the universe, as he, unlike God, could only be in one place at a time.
The period’s principal patron of the arts, the Church was therefore able to put a fair bit of pressure on artists to work differently, and over the course of time the very science of perspective was forgotten altogether.
To get back to Filippo Brunelleschi, he created two perspective panels in an elaborate experiment showing the miraculous perceived depth that could be achieved by drawing a piece of architecture a certain way – in his most famous example, the Church of St Giovanni, Florence’s Baptistery.
He took extremely accurate sightings of the church from just inside the doorway of the Cathedral opposite to paint its picture onto his panel; next, he cut a peephole through where the vanishing point fell on the picture, that was “the size of a lentil” on the painted side, and opening up “conically” on the back. By holding up the panel with its unpainted side to his face, he looked through the peephole at a mirror to see an astonishingly three-dimensional image for the time of the Baptistery. Having a polished silver area on the panel made the reflected image even more impressive as the actual sky was reflected on the perspective panel.
What makes Brunelleschi’s experiment so interesting is that, before the theory and discipline of linear perspective was even developed, he found a way to place himself, the viewer, behind the subject of his painting, to look down the length of the centric ray from the wrong end and to see the subject’s scale image on the back of the picture plane!
This laid the groundwork for his fellow Florentine Leon Battista Alberti to write his 1435 “On Painting” treatise, thereby formalizing the rules of linear perspective. As the convention of linear perspective gained ground it participated in ushering in the Early Renaissance and the Humanistic view, in re-establishing a single viewpoint in Western art and again placing Man at the center of the universe.