Method of giving a sense of depth on a flat or shallow surface, utilizing such optical phenomena as the apparent convergence of parallel lines and diminution in size of objects as they recede from the spectator. Perspective is by no means common to the art of all epochs and all peoples. For example, the pictorial art of the ancient Egyptians, although a richly developed tradition, did not take account of the optical effects of recession. Systematic, mathematically founded perspective, based initially on a fixed central viewpoint, was developed in Italy in the early 15th century, when it was invented by Brunelleschi, described by Alberti in his treatise De pictura, and put into majestic practice by Masaccio. Various names are given to this type of perspective—geometric, linear, mathematical, optical, Renaissance or scientific perspective—which remained one of the foundations of European painting until the late 19th century. In pre-Renaissance Europe and in the East, more intuitive systems of representing spatial recession were used. In medieval paintings, for example, lines that would in strict perspective converge are often shown diverging (this ‘inverted perspective’ can look much more convincing in practice than it sounds in theory); and in Chinese art ‘parallel perspective’ was a common convention in the depiction of buildings. See also aerial perspective.