Unforgiven was first held as the pay-per-view (PPV) in April 1998; In Your House was a series of monthly PPV shows first produced by the World Wrestling Federation (WWF, now WWE) in May 1995. The In Your House branding was retired following February 1999's event, as the company moved to install permanent names for each of its monthly PPVs. Unforgiven then returned in September 1999 as its own PPV event, thus establishing Unforgiven as the annual September PPV for the promotion. The 2001 event was the fourth event in the Unforgiven chronology and took place on September 23 at the Mellon Arena in Pittsburgh, Pennsylvania. It was also the last held under the WWF name, as the promotion was renamed to World Wrestling Entertainment (WWE) in May 2002. It was also the last Unforgiven held before the promotion introduced the brand extension in March 2002, a storyline subdivision in which the promotion divided its roster into two separate brands, Raw and SmackDown!, where wrestlers exclusively performed.