As NWA champion, Buddy Rogers’ bookings were controlled by Toots Mondt, promoter in the Northeast. The other NWA promoters were dissatisfied because Mondt rarely let Rogers defend the belt outside the Northeast. Mondt and Vince McMahon Sr. wanted to keep Rogers and the NWA title, but Rogers didn’t want to lose his $25,000 deposit on the belt. So Rogers lost the NWA title to Lou Thesz in Toronto on January 24, 1963.
Buddy Rogers was not recognized as the first WWWF champion right after losing to Thesz. Instead, Rogers was awarded the WWWF title in mid-April 1963, with the explanation that he has won a (fictitious) tournament in Rio de Janeiro. Buddy Rogers lost the title to Bruno Sammartino a month later on May 17, 1963.
1971-1983, the WWF joined the NWA as a regional promotion and the WWF World title was dropped in status to the WWF title, a regional title.
1979: Changed from WWWF (World Wide Wrestling Federation) to WWF (World Wrestling Federation).
Shortly after, the WWF phased out their North American title and replaced it with the Intercontinental title.