Simplify the following text for a Grade 10 native English-speaking person.
Original: The Invasion was a wrestling storyline in the World Wrestling Federation ( WWF ) that began after the WWF bought World Championship Wrestling ( WCW ) .
Simplified: For the pay-per-view , see WWF InVasion . The Invasion was a professional wrestling storyline in the World Wrestling Federation ( WWF ) ( known now as World Wrestling Entertainment or WWE ) that began shortly after the WWF 's purchase of World Championship Wrestling ( WCW ) .