Until the advent of gas lighting, most of the acting took place at the front of the stage, with the scenery on the main stage providing a background for the performers. This was more than a theatrical concept or stylistic preference. The front of the stage was where the footlights and the bright auditorium chandeliers supplied adequate illumination, in contrast to the dimly lit scenic area. In the age of gaslight, with the development of lighting positions above the stage and the use of much brighter light, the separation of stage lighting from the auditorium lighting became possible. This, in turn, allowed for the integration of the actors and the scenery. Now the actors could be placed behind the proscenium, performing on a set rather than in front of it. Once the distinction between auditorium and stage lighting systems was made it was possible to extinguish the auditorium sun burner chandelier during the performance. The custom of darkening the auditorium became customary by the end of the 19th century.