There are three prominent areas or spaces to a painting's overall composition, from the picture plane (which is the bottom edge of the painting/canvas) transcending upwards towards the center of the painting and continuing to move into the remainder of the picture. The areas of the painting are as follows, from area closest to the viewer to the area that is furthest away: the foreground, middle-ground and background.
The background is the area of simulated space which is furthest away from the spectator, that is the background is the furthest away in the illusionary space. Artists created illusionistic space by depicting figures, objects, architecture and topographical features receding into the painting - the sense of space is often exaggerated by these features being shown receding into one or more of the different spaces within the composition. When an artist tries to create the impression of space receding into a painting, the effect on the viewer is to create an illusion of space seeming to either be closer to the viewer whilst other parts seem further away. As the development of perspective was crucial to creating a more naturalistic form of art.