Basic history of film trailers

The first trailer was shown in a theatre in 1913 for the musical Pleasure seekers shown on Broadway. Originally Trailers used to trail a film hence the name Trailer. However it was noticed after years of showing them after that the audience would leave and wouldn’t watch them, therefore now showing trailers before films, this now means that people will be when visiting the cinema having to watch the trailers for other films, this can be a huge way of attracting people to come and watch thier film and would be a main selling point for most films.