Jake LaMotta famously said of Sugar Ray Robinson, “I fought him so often, I almost got diabetes.

Over the years, LaMotta has used that line again and again, and that’s okay because he fought Sugar Ray again and again—six times in all from 1942 through “The St. Valentine’s Day Massacre in 1951.

On May 22, Israel Vazquez and Rafael Marquez will clash for a fourth time in a rivalry that ranks with the best in boxing history. From March 2007 through March 2008, Vazquez and Marquez battled three times for the WBC super bantamweight title. Marquez won the first by stoppage; Vazquez won the rematch by stoppage; and with the rubber match in the balance going into the final round, Vazquez mounted an inspired 12th-round rally to win by split decision (one point on the deciding card).

The second and third bouts were selected as Fight of the Year.

As was the case with Robinson and LaMotta, Vazquez and Marquez draw the best from each other, and as a result, their fights have featured incredible intensity, high drama, and boxing at its highest level. But what separates Vazquez and Marquez from other historic pairings is that they’re more alike than different. Both are Mexican, both are aggressive boxer-punchers of similar size, and each readily acknowledges the greatness of the other.

Instead of bad blood, there’s mutual respect. That by itself separates the rivalry from legendary grudges like Robinson-LaMotta, Sugar Ray Leonard-Roberto Duran, Sandy Saddler-Willie Pep, and Marco Antonio Barrera-Erik Morales.

There have been several notable three-fight series in the modern era, including Barney Ross-Jimmy McLarnin, Ezzard Charles-Archie Moore, Nino Benvenuti-Emile Griffith, Muhammad Ali-Ken Norton, Roberto Duran-Esteban DeJesus, and the most savage of all, Tony Zale-Rocky Graziano.

More recently, the trilogies that stand out include Riddick Bowe-Evander Holyfield, Arturo Gatti-Micky Ward, Roy Jones-Antonio Tarver, and Michael Carbajal-Chiquita Gonzalez.

But there have been precious few series comprised of four fights or more. Bonded forever, Vazquez and Marquez are about to add their names to the following:

*Jack Britton-Ted “Kid Lewis (1915-1921): Believe it or not, Britton, an American boxer, and Lewis, a British puncher, traded blows 20 different times. They also traded the world welterweight title during their hall of fame careers.

*Robinson-LaMotta (1942-1951): Only the sixth and final fight was contested with a world title at stake (middleweight). In February ’43, LaMotta dropped Robinson and claimed his only victory in the series. (It was Sugar Ray’s only loss in his first 133 fights.) But here’s what’s incomprehensible by today’s standards: Only three weeks after LaMotta’s win, they fought again. And better yet, Robinson flew to New York and took a bout in between.

*Gene Tunney-Harry Greb (1922-1925): Tunney, who was the naturally bigger man, was brutalized over 15 rounds in the first of their five fights. It was the only loss of his stellar career. He won the next four, two of which were, technically at least, no-decision bouts.

Tunney and Greb never met for a world title, though Greb, universally recognized as one of the three or four greatest middleweight ever, was the reigning 160-pound king during bouts three, four, and five.

· Jack Britton – Ted Kid Lewis (1915 – 1921) : 20 Fights

· Gene Tunney – Harry Greb (1922 – 1925): Five Fights

· Sugar Ray Robinson – Jake LaMotta (1942 – 1951): Six Fights

· Beau Jack – Bob Montgomery (1943-1944): Four Fights

· Sandy Saddler – Willie Pep (1948 -1951): Four Fights

· Beau Jack – Ike Williams (1948-1955): Four Fights

· Jersey Joe Walcott – Ezzard Charles (1949-1952): Four Fights

· Sugar Ray Robinson – Gene Fullmer (1957 – 1961): Four Fights

· Bobby Chacon – Rafael “Bazooka Limon (1975 -1982): Four Fights

· Azumah Nelson – Jesse James Leija (1993-1998): Four Fights

*Sandy Saddler-Willie Pep (1948-1951): The world featherweight title was at stake in all four bouts, but the series is perhaps best remembered for some of the dirtiest big-fight tactics ever witnessed. Saddler won three of four. Pep’s decision win in ’49, however, was the most memorable performance—and arguably the greatest moment of the defensive master’s fantastic career.

*Sugar Ray Robinson-Gene Fullmer (1957-1961): A faded Robinson went 1-2-1, with at least a portion of the middleweight title at stake in each fight. In the second bout, Robinson regained the world title by knocking out his steel-chinned rival with a left hook that was instantly labeled “the perfect punch.

*Bobby Chacon-Bazooka Limon (1975-1982): This featured a Mexican-American (Chacon) vs. a Mexican-National, and the animosity was evident each time they fought. Chacon went 2-1-1; in the fourth bout, which was ‘82’s Fight of the Year, he twice rose from the canvas and scored a knockdown in the 15th round that turned out to be the difference on the cards.

*Azumah Nelson-James Leija (1993-1998): In the most recent major four-fight series, Leija edged Ghanaian legend Nelson 2-1-1 on the scoreboard. The first three fights were contested for the 130-pound title.

*Beau Jack-Ike Williams (1948-1955); Beau Jack-Bob Montgomery (1943-1944): These three champions engaged in an extended round-robin (Williams fought Montgomery twice) that defined the lightweight division for more than a decade. Jack went 0-3-1 vs. Williams and 2-2 vs. Montgomery.

*Ezzard Charles-Jersey Joe Walcott (1949-1952): The heavyweight title was on the line in all four of their bouts, with Charles winning the first two, and Walcott the last two. In fight number three, the title changed hands from one punch, a Walcott left hook in round seven.

Clearly, rivalries of four fights or more have become increasingly rare. It’s virtually impossible to imagine the first three fights of the Vazquez-Marquez matchup being any more exciting or absorbing than they were. Still, the fighters are willing to test each other again, knowing full well that at this advanced stage of their respective careers, they’re going to have to suffer for their craft.

Both Vazquez and Marquez know how difficult fight number four will be. Twenty-five shared rounds have convinced them of that. Yet they find themselves drawn to each other yet again.

You want an explanation? Here’s a try: It’s not for us to understand, but rather to admire, enjoy, and wonder at.