Perspective creates an illusion of three-dimensional space on a two-dimensional picture surface. Objects in the background appear smaller than those in the foreground.
The 'single point' system (linear perspective) was invented by Brunelleschi in Florence in relation to his architecture. It is mathematically constructed so that all receding parallel lines appear to converge towards each other, eventually meeting at a single point, the vanishing point. This system was used by artists from the early 15th century in Florence, and codified by Alberti in 'De Pictura'.
Netherlandish painters in the early 15th century seem to have created a convincing illusion of three-dimensional space empirically, employing linear perspective without the system devised in Italy.