Undisputed championship
An undisputed championship is a professional wrestling term for a champion who has obtained all of the major individual championships in his field during his era. The undisputed championship is an extremely rare and prestigious accomplishment.
The first undisputed champions
The reported first undisputed champion was Georg Hackenschmidt, who won a series of tournaments in Europe, including a world championship tournament to win the title. Amongst the other tournaments he won were the annual major tournaments in Paris, France; Hamburg, Germany; St. Petersburg, Russia; Elberfeld, Germany; and Berlin, Germany. Hackenschmidt also defeated European Greco-Roman Champion Tom Cannon on September 4, 1902 in Liverpool, England to become the first undisputed World Heavyweight Champion.
The only other reigning champion with claim to the belt at the time was Tom Jenkins, who held the American Heavyweight Championship, which unified the American Greco-Roman Championship with the American Catch-As-Catch Can Championship. Jenkins was eventually defeated by Frank Gotch, who took over as the only man with a potentially legitimate claim to being "the true champion".
Hackenschmidt and Gotch finally met in the ring on April 3, 1908 in Chicago, Illinois. Gotch defeated Hackenschmidt to win the World Heavyweight Championship, then abandoned the American Heavyweight Championship in a process similar to today's championship unification. Gotch wrestled for several years before retiring as undisputed champion
Other wrestlers who were recognized as the only major World Champion following Gotch's retirement were Earl Caddock, Joe Stecher, Ed "Strangler" Lewis, Stanislaus Zbyszko, and Wayne Munn. The championship became disputed in the late 1920s, and remained that way for over 20 years, when several major World Championships split from the primary title (namely, Boston's American Wrestling Association World Championship, the National Boxing Association (later, National Wrestling Association) World Championship of Wrestling, and the New York State Athletic Commission World Championship). Other governing bodies would create their own version of the World Championship in the 1930s and '40s, as well.
Lou Thesz and the National Wrestling Alliance
After Gotch's retirement, several other men proceeded to hold the then World Heavyweight Title, including periods of time where the National Wrestling Association formed a second World Heavyweight Title to contend with the formerly undisputed belt. From that point onward, there was no undisputed champion, as multiple men laid claim to the title without ever backing it up by defeating multiple other contenders.
This all changed in July 1948, when the National Wrestling Alliance (NWA) was formed by multiple promotions and awarded the NWA World Heavyweight Championship to Orville Brown. After Brown suffered career-ending injuries in an automobile accident on November 1, 1949, the NWA recognised Lou Thesz as the champion. Thesz had earlier won the National Wrestling Association's World Heavyweight Championship on July 10, 1948 from Wild Bill Longson.
Thesz traveled to many areas and defeated various champions. He defeated the American Wrestling Association (a Boston based federation different from Verne Gagne's more famous organization of the same name) World Champion Gorgeous George on July 27, 1950 in a non-title match, and, finally, Baron Michele Leon on May 21, 1952 for the Los Angeles Olympic Auditorium World Heavyweight Title.
In light of having unified 3 of the major world heavyweight championships of his time (as well as numerous other lesser-prestige titles) and defeating the reigning AWA World Champion in a non-title match (a major title that was abandoned soon after), Thesz became the Undisputed Champion for some time. From that point onward, the National Wrestling Alliance World Heavyweight Title (the belt that Thesz opted to keep as the designation of all the championships he'd won) became the undisputed world heavyweight title for all contenders to seek.
This, however, would change over the years and decades to come as professional wrestling grew and evolved. The American Wrestling Association, owned by Verne Gagne split off from the NWA and declared their primary singles title a world title in 1960. The World Wide Wrestling Federation, owned by Vince McMahon, Sr. followed suit in 1963 and declared their major singles title a world championship. Many other NWA affiliated promotions would split from the NWA over the years with Ted Turner's World Championship Wrestling in 1993, and Tod Gordon's Eastern Championship Wrestling in 1994. Each of these promotions declared their primary singles championship to be a world championship.
World Wrestling Federation/Entertainment
When the AWA folded in 1991 with Larry Zbyszko as their final champion, one of the last major world titles was gone. Meanwhile, the NWA became less prevalent during the Monday night television ratings war that engrossed the WWF and WCW during the 1990s. ECW shut down in 2001 with Rhino as their last champion, seemingly leaving the group of prominent world championships down to two, and with WCW's subsequent fall and purchase by the WWF during the same year, the World Wrestling Federation Championship remained.
WWF took full advantage of their situation, unifying the unbranded "World Championship" (formerly the WCW World Heavyweight Championship) and WWF World Championship at Vengeance in 2001, with Chris Jericho becoming the first Undisputed WWF Champion in over 50 years. The championship was then represented by the belts of its two predecessors until a singular belt design was commissioned. By May 2002 the WWF had been renamed to World Wrestling Entertainment and the Undisputed WWE Championship, as it was now called, became the top championship of the promotion.
With the purchase of WCW during the previous year, WWE's roster had doubled in size and with newly obtained properties and a desire to further expand, the promotion was essentially divided in what became known as the WWE Brand Extension. This resulted in WWE's two main programs, Raw and SmackDown, becoming distinct brands, acting as complementing promotions under WWE. The WWE Undisputed Championship was then consequently shared between both brands and soon conflict began brewing over the title. In late August 2002 after becoming the youngest WWE world champion at the time by winning the WWE Undisputed Championship, Brock Lesnar and his title were made exclusive to SmackDown. To remedy this, the Big Gold Belt was brought back to represent the new World Heavyweight Championship and became Raw's top championship, thus making the WWE Championship no longer Undisputed.
In 2011, the WWE Championship was temporarily referred to as "undisputed" again. After a storyline in which John Cena and CM Punk both claimed the WWE Championship, the two faced off at the 2011 Summerslam, resulting in a single title holder. This was not, however, the same as the Undisputed title that existed between 2001 and 2002, as the World Heavyweight Championship was unaffected.
Titles disputed again
During that same year, two current major promotions started business; Total Nonstop Action Wrestling (TNA) and Ring of Honor (ROH). TNA took the quick route to success, gaining usage of the NWA titles through a working agreement with the National Wrestling Alliance (NWA). With the NWA World Heavyweight Championship back in the spotlight, TNA presented the title defenses on an international scale. TNA eventually left the NWA in 2007 and thus replaced the NWA World Heavyweight Championship with their own TNA World Heavyweight Championship. Meanwhile, Ring of Honor had established their ROH World Championship, defending the title internationally over several continents by 2003.
Additionally, following ECW's original closure in 2001, WWE had purchased its assets and remaining properties. In 2006, WWE re-established the Extreme Championship Wrestling franchise to complement the existing Raw and SmackDown franchises while the ECW World Heavyweight Championship was recommissioned for the new ECW brand. The brand and the title remained active within WWE until 2010.
At this moment there is no undisputed world heavyweight title. The promotion with most potential claim to such legacy is WWE, who unified their WWE Championship and World Heavyweight Championship on December 15, 2013, to form the WWE World Heavyweight Championship.