The American professional wrestling promotion WWE has been broadcasting pay-per-view (PPV) events since the 1980s, when its classic "Big Four" events (Royal Rumble, WrestleMania, SummerSlam, and Survivor Series) were first established—the company's very first PPV was WrestleMania in 1985. The company's PPV lineup expanded to a monthly basis in the mid-1990s following the introduction of the In Your House series of pay-per views before expanding even further in the mid-2000s during the first WWE brand extension. Following WWE's original brand extension in 2002, the company promoted two touring rosters, Raw and SmackDown, representing its television programs, Raw and SmackDown. The traditional "Big Four" continued to showcase the entire roster, while the remaining PPV events alternated between Raw and SmackDown cards. In March 2007, WWE announced that all subsequent PPV events would feature performers from all brands. In 2008, all WWE PPV events began broadcasting in high-definition.
