In 1991, World Championship Wrestling (WCW), another NWA territory, created the WCW World Heavyweight Championship and it was just as important as the NWA world title. WCW then left the NWA and became a rival promotion to the WWF. Both promotions became popular, and fought the "Monday Night Wars". This was a fight to see who could get better ratings on TV. Near the end of the ratings war, WCW started to lose money, and the Monday Night Wars ended in March 2001 with WWF buying WCW. After that, WWF had all of WCW's videos, some of their wrestlers and championships, and other things. The group of wrestlers who were in WCW joining the WWF was called "The Invasion". After this, the WCW World Championship was made one with the WWF World Championship, at Vengeance 2001 in December. At the show, Chris Jericho beat The Rock to win the WCW World Championship, and Stone Cold Steve Austin to win the WWF World Championship. Because of this, Chris Jericho was the last WCW World Champion and the Undisputed WWF World Champion as there was no dispute over what the most important prize in professional wrestling was anymore.