When Wladimir Klitschko steps into the ring with Anthony Joshua on Saturday night, it will be the 29th world title fight of his outstanding career. Only a handful of men in history have managed more.

Here is a definitive list of fighters who have fought in the most world title bouts (counting the four main sanctioning organizations – WBA, WBC, IBF and WBO – with the total number of title bouts followed by title-bout records):

Julio Cesar Chavez, 37, 31-4-2 (21) – The Mexican icon is the gold standard that all other Mexican fighters are measured against. Chavez won titles at three weight classes, 130, 135 and 140 pounds, stretching a mammoth 16 years, from 1984 to 2000.

Bernard Hopkins, 33 (36 counting RING title bouts), 24-5-2 (13), 2 No Contests – The “Immortal B-Hop” was pretty much untouchable at middleweight for 10 years when he cleaned out the 160-pound division and unified all four major sanctioning organization belts before heading to light heavyweight where he won multiple titles. [Editor’s note: Hopkins won THE RING light heavyweight championship by outpointing Antonio Tarver. He defended the title with a unanimous decision over Winky Wright before losing it via split decision to Joe Calzaghe.]

Omar Narvaez, 31, 28-2-1 (12) – The Argentine Olympian, who reigned longer than any flyweight in history, vacated his 112-pound belt just one defense shy of Thai legend Pongsaklek Wonjongkam’s divisional record mark. He then enjoyed more success at 115-pounds where he made an additional 11 title defenses before unraveling last year against upstart Naoya Inoue.

Oscar De La Hoya, 29, 24-5 (17) — After winning gold at the 1992 Olympics, “The Golden Boy” turned pro at 130 pounds, where he won his first world title. He went on to be one of history’s most popular fighters as well as the sport’s first six-weight world champion, beating 24 world titleholders along the way.

Virgil Hill, 29, 24-5 (8) – The 1984 Olympic silver medalist had two light heavyweight title reigns of 10 defenses before closing out his hall-of-fame career by twice winning the WBA cruiserweight title.

Abe Attell, 28, 21-3-4 (12) – The former featherweight world champion, who ruled in the early 1900s, was heavily associated with the mob and was infamously involved in the 1919 world series betting scandal, leading many to question the authenticity of many of his fights; however at least 27 or 28 were billed as “world championship bouts” at the time. [Editor’s note: The Boxing Register, the official record book of the International Boxing Hall of Fame, credits Attell with 14 successful title defenses and notes that “his claim to the championship was disputed” at times during his 11-year reign.]

Wladimir Klitschko, 28, 25-3 (19) – The respected if not lauded former heavyweight champion, who unified the IBF, WBO and WBA belts (as well as earned THE RING title), surpassed Louis for most heavyweight title fights when he faced (and lost to) Tyson Fury in November 2015. “Dr. Steelhammer” was in striking range of two other records currently belonging to Louis – longest reign and most consecutive defenses.

Joe Louis, 27, 26-1 (22) – “The Brown Bomber,” arguably the greatest heavyweight champion in history, holds the record for the most consecutive title defenses, 25, and the longest uninterrupted title reign, 11 years and 7 months, in one weight class.

Dariusz Michalczewski, 27, 25-2 (20) – The hard-charging Pole was a two-weight world champion though almost all of his success was at 175 pounds. After going 48-0, with 38 knockouts, he lost to the late Julio Gonzalez when his rugged pressure-fighting style finally caught up with him.

Floyd Mayweather Jr., 26, 26-0 (10) – The highest paid boxer in history won 10 world titles (the WBC 147- and 154-pound titles twice) in five divisions – junior lightweight, lightweight, junior welterweight, welterweight and junior middleweight – and beat 22 world titleholders along the way.

Ricardo Lopez, 26, 25-0-1 (19) – Half of the long-reigning WBC strawweight champion’s fights were world title fights. The masterful Mexican technician, who retired unbeaten in 52 bouts, even stepped up to junior flyweight late in his career to become a two-weight titleholder.

Pongsaklek Wongjongkam, 26, 22-2-2 (8) – One of the greatest flyweights in history, the Thai southpaw enjoyed one lengthy title reign before losing his belt and, as an aging underdog, proved his mettle by unseating much younger Koki Kameda to regain his old title.

Henry Armstrong, 26, 22-3-1 (17) – The popular and relentless slugger did what was almost unthinkable at the time, winning titles at featherweight, lightweight and welterweight in the days when there were only eight weight classes. He held Ceferino Garcia to a draw – which many believed he deserved to win – when the two contested for a version of the middleweight title (though only recognized in New York and California).

Roy Jones Jr., 25, 22-3 (15) – Many believe the four-weight former champion is one of the very best fighters ever. The dynamic boxer-puncher beat Hopkins, James Toney, Mike McCallum and Antonio Tarver, among others, in championship bouts. [Editor’s note: Jones also took part in one interim “world title” fight.]

Muhammad Ali, 25, 22-3 (14) – The self proclaimed “Greatest” enjoyed two lengthy heavyweight title reigns that helped him post the numbers he needed to get on the list. Ali, arguably the best big man ever along with Louis, beat a who’s who of top contenders from the Golden Age of the heavyweight division.

Marco Antonio Barrera, 25 (30 counting RING title bouts), 21-4 (12) – The terrifically talented Mexican, who could box and bang, won world titles at junior featherweight, featherweight and junior lightweight. [Editor’s note: Barrera arguably competed in 30 “world title” bouts during his career. His 2001 fight with Naseem Hamed, who had defeated all of the featherweights who held major belts going into their bout, was viewed by many fans and boxing media as being for “universal recognition as 126-pound champ.” Barrera won the fight and defended that universally recognized title with a sixth-round stoppage of Enrique Sanchez. Barrera won THE RING’s featherweight title when he beat WBC beltholder Erik Morales in their 2002 rematch. He defended it twice – against Johnny Tapia and Kevin Kelley – before losing it to Manny Pacquiao in 2003.]

Larry Holmes, 25, 20-5 (14) – Many unfairly believe Holmes merely bridged the heavyweight division between the popular reigns of Ali and Mike Tyson, but he was a highly competent and dominant champion in his own right who fought behind one of the best jabs ever.

George Dixon, 25, 19-4-2 (11) – Dixon was the first black world champion in any weight class. He held world titles at bantamweight in the 1890s and reigned supreme at featherweight later in the decade. The Canadian was regarded by Nat Fleischer as the greatest bantamweight ever.

Terry Norris, 25, 19-6 (14) – The supremely gifted Texan beat more than a dozen top-notch fighters of the 1990s during three title reigns at 154 pounds. He was only let down by his fierce in-the-ring temper and his shaky chin.

Evander Holyfield, 25, 16-7-2 (9) – The only man ever to unify the cruiserweight and heavyweight divisions. Fought a who’s who of the heavyweight division from his era, including Mike Tyson, Riddick Bowe, Larry Holmes, George Foreman and Lennox Lewis.

Narrowly missing the cut are a host of other standouts, including 24-title-bout vets Azumah Nelson, 18-4-2 (12), Hilario Zapata, 18-5-1 (4), Chris Eubank, 17-5-2 (5), Felix Sturm, 17-5-2 (5), Manny Pacquiao 18-3-2 (8) [Editor’s note: Pacquiao won THE RING featherweight championship by stopping lineal champion Marco Antonio Barrera, and defended it versus Fahsan 3K Battery. He earned the vacant RING junior lightweight title by edging Juan Manuel Marquez in their hotly contested rematch, and also won THE RING junior welterweight belt beating lineal champion Ricky Hatton] and Emile Griffith 16-8 (5).

Fighters who had 23 title bouts: Manuel Ortiz, who went 21-2 (11), Wilfredo Gomez, 20-3 (18) in title bouts including a record 17 KO defensse of the WBC 122-pound title, Ratanapol Sor Voraphin, 20-3 (16), Pernell Whitaker, 19-3-1 (4), Miguel Cotto, 19-4 (16), and Erik Morales 18-5 (12).

The 22 club: Joe Calzaghe, 22-0 (11), Sven Ottke, 22-0 (5), Eusebio Pedroza, 19-2-1 (11), Arthur Abraham, 19-3 (9), Alexis Arguello, 19-3 (17), Ivan Calderon, 18-3-1 (2), Fernando Montiel 17-5 (13), Roberto Duran, 16-6 (13), Sugar Ray Robinson 16-6 (10), Shane Mosley, 15-7 (11) and Daniel Zaragoza 14-5-3 (5).

The 21 club: Felix Trinidad, 20-1 (16), Myung Woo Yuh, 20-1 (10), Wilfredo Vazquez Sr., 16-4-1 (9), Jorge Arce, 15-6 (9). [Editor’s note: Arce also took part in eight “interim” world title fights.] and Tony Canzoneri, 11-9-1 (2).

The 20 club: Khaosai Galaxy, 20-0 (17), Jung Koo Chang, 16-4 (7) and Manuel Medina 10-11 (2).

Most successful consecutive title defenses (top three in each division):

Heavyweight – Joe Louis – June 22, 1937-March 1, 1949 (11 years 8 months).
Cruiserweight – Johnny Nelson – March 27, 1999-Sept. 22, 2006 (7 years 6 months).
Light heavyweight – Archie Moore – Dec. 17, 1952-May 12, 1962 (9 years 2 months).
Super middleweight – Joe Calzaghe – Oct. 11, 1997-Sept. 26, 2008 (10 years 11 months).
Middleweight – Bernard Hopkins – April 29, 1995-July 16, 2005 (10 years 3 months).
Junior middleweight – Gianfranco Rosi – July 15, 1989 –Sept. 17, 1994 (5 years 2 months).
Welterweight – Felix Trinidad – June 19, 1993-March 3, 2000 (6 years 9 months).
Junior welterweight – Julio Cesar Chavez – May 13, 1989 –Jan. 29, 1994 (4 years 8 months).
Lightweight – Artur Grigorian – April 13, 1996-Jan. 3, 2004 (7 years 9 months).
Junior lightweight – Flash Elorde – March 16, 1960-June 15, 1967 (7 years 3 months).
Featherweight – Johnny Kilbane – Feb. 22, 1912 – June 2, 1923 (11 years 3 months).

Junior featherweight – Wilfredo Gomez – May 21, 1977-April 1983 (5 years 11 months).
Bantamweight – Orlando Canizales – July 9, 1988-January, 1994 (6 years 6 months).
Junior bantamweight – Khaosai Galaxy – Nov. 21, 1984-January 1992 (7 years 1 month).
Flyweight – Omar Narvaez – July 13, 2002-May 15, 2010 (7 years 10 months).
Junior flyweight – Myung Woo Yuh – Dec. 8, 1985 –Dec. 17, 1991 (6 years).
Strawweight – Ricardo Lopez – Oct. 25, 1990-Oct. 1, 1999 (almost 9 years).

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