Complex sentence: It was founded by Sony Pictures Entertainment and The Jim Henson Company in 1997, prior to that Henson films were released under the production banners of Henson Associates or Jim Henson Productions.
Split into simpler sentences: It was founded by Sony Pictures Entertainment and The Jim Henson Company in 1997. Prior to that Henson films were released under the production banners of Henson Associates or Jim Henson Productions.