Winning one World Series is hard enough, but there have only been 14 teams to repeat as winners. MLB.com takes a look back at those repeat champions, beginning with the most recent.
1998-2000 Yankees (three straight World Series wins)
1998: Yankees defeat Padres, 4-0
1999: Yankees defeat Braves, 4-0
2000: Yankees defeat Mets, 4-1
The most recent Yankees dynasty featured a three-peat that started with the 1998 Yankees, one of the greatest teams of all time. Behind the Core Four -- Derek Jeter, Jorge Posada, Andy Pettitte and Mariano Rivera -- the Bronx Bombers won a franchise-record (and then-AL-record) 114 games, then went 11-2 in the postseason and swept the Padres in the World Series.
New York beat the Braves in 1999 -- another World Series sweep that included wins over Greg Maddux and John Smoltz and a game-tying rally in the eighth inning against Tom Glavine. And in 2000, the Yankees won the Subway Series World Series over the Mets in five games, the first all-New York Fall Classic since the last bout of the Yankees-Brooklyn Dodgers rivalry in 1956.
1992-93 Blue Jays
1992: Blue Jays defeat Braves, 4-2
1993: Blue Jays defeat Phillies, 4-2
The 1992 Blue Jays became the first non-U.S. team to win the World Series when they beat the Braves in six games. They were led by Hall of Fame second baseman Roberto Alomar, who hit .310 and stole 49 bases, and the power-hitting tandem of Joe Carter and Dave Winfield, who belted 60 homers between them and drove in a combined 227 runs.
The 1993 team then repeated behind the "WHAMCO" lineup -- Devon White, Rickey Henderson, Alomar, Paul Molitor, Carter and John Olerud. Of course, the '93 Blue Jays are best remembered for winning the World Series in one of the most iconic moments in postseason history: Carter's series-ending walk-off home run in Game 6 at the SkyDome.
1977: Yankees defeat Dodgers, 4-2
1978: Yankees defeat Dodgers, 4-2
Not only did the Yankees repeat in 1977-78 -- their first two championships under George Steinbrenner -- they won a World Series rematch, beating the Dodgers both years. Both seasons had a signature moment. In 1977, it was Game 6 of the Fall Classic -- the game Reggie Jackson became Mr. October. Jackson homered three times in three at-bats, on three total pitches, off three different Dodgers pitchers, in the Yankees' series-clinching victory.
In '78, it was the AL East tiebreaker game -- the Bucky Dent Game. The Yankees and Red Sox had finished the regular season tied for first place, forcing a one-game playoff at Fenway Park. With the Yankees trailing, 2-0, in the seventh inning, Dent belted a go-ahead three-run homer over the Green Monster, cementing his legacy in the rivalry's history.
1975: Reds defeat Red Sox, 4-3
1976: Reds defeat Yankees, 4-0
The Big Red Machine reached its pinnacle with back-to-back World Series titles in 1975 and '76. The Reds were one of the most dangerous top-to-bottom teams ever assembled. Joe Morgan was the NL MVP in both of these seasons; Pete Rose was the World Series MVP one year, Johnny Bench the next. And that's just scratching the surface of the talent they had.
The 1976 World Series was a sweep, with the Reds breezing past the Yankees before New York's own repeat that started the next year. But the '75 World Series was a seven-game classic against the Red Sox. Ironically, the iconic moment it produced was Carlton Fisk waving his 12th-inning walk-off home run fair in Game 6 at Fenway Park. But it was the Reds who won the series in Boston the next night, on Morgan's tiebreaking single in the ninth inning.
1972-74 A's (three straight World Series wins)
1972: A's defeat Reds, 4-3
1973: A's defeat Mets, 4-3
1974: A's defeat Dodgers, 4-1
The 1970s were full of repeat champs -- the A's were the first of three different teams to win consecutive World Series. With this run, the A's also became the only other Major League franchise besides the Yankees to win at least three straight World Series titles.
The first two both went the full seven games. The A's barely edged the Reds in 1972, staving off Cincinnati's comeback from down 3-1 in the series thanks to Catfish Hunter and Rollie Fingers' shutdown relief efforts in the deciding Game 7. The next year, Oakland beat the Mets; Reggie Jackson, though he wasn't Mr. October quite yet, did win World Series MVP (and was the regular-season AL MVP, too).
1961: Yankees defeat Reds, 4-1
1962: Yankees defeat Giants, 4-3
In 1961, Roger Maris broke Babe Ruth's single-season home run record, hitting No. 61 on the final day of the regular season. That won Maris his second straight AL MVP, and right behind him was teammate Mickey Mantle, who hit a career-best 54 home runs of his own that year. The Yankees then cruised to a five-game World Series win over the Reds, with Whitey Ford the series MVP after throwing a shutout in Game 1 and five scoreless innings to win Game 4.
The next year's Fall Classic was much more tightly contested, with the Giants pushing the Yankees to seven games in their first World Series appearance since moving to San Francisco. The Yankees prevailed, but the series came down to the final at-bat. With the Giants down 1-0 in the bottom of the ninth inning of Game 7 at Candlestick Park, runners on second and third and two outs, Willie McCovey ripped a line drive that was caught by Yankees second baseman Bobby Richardson to end the series.
1949-53 Yankees (five straight World Series wins)
1949: Yankees defeat Dodgers, 4-1
1950: Yankees defeat Phillies, 4-0
1951: Yankees defeat Giants, 4-2
1952: Yankees defeat Dodgers, 4-3
1953: Yankees defeat Dodgers, 4-2
The Yankees have won three World Series in a row (1998-2000). They've won four World Series in a row (1936-39). And they've won five World Series in a row -- the longest championship streak in MLB history. This Yankees dynasty encompassed both the twilight of the DiMaggio era and the dawn of the Mantle era. Joltin' Joe won the final three rings of his career from 1949-51, while a young Mantle got his first three from 1951-53. Fellow Yankee legends Yogi Berra and Phil Rizzuto were on all five championship teams.
The Yankees' run was bookended by three World Series wins over the Dodgers (one to open the streak in 1949, and two to close it in '52 and '53), with the other two coming against the Phillies in 1950 and the Giants in '51. Only Brooklyn, in 1952, pushed the Yankees to seven games -- but the first two of Mantle's record 18 career World Series home runs made the difference in Game 6 and Game 7.
1936-39 Yankees (four straight World Series wins)
1936: Yankees defeat Giants, 4-2
1937: Yankees defeat Giants, 4-1
1938: Yankees defeat Cubs, 4-0
1939: Yankees defeat Reds, 4-0
With Babe Ruth having played his final Yankees season in 1934, it was Lou Gehrig who led the Yankees to their 1936 title, the franchise's first without the Babe. New York would win the next three Fall Classics, too, in the final years of Gehrig's career before his health failed him. These four seasons, 1936-39, were also the first four of DiMaggio's career.
The Yankees teams of the late '30s had other Hall of Famers, too -- Bill Dickey, Tony Lazzeri, Joe Gordon, Red Ruffing, Lefty Gomez. They rolled to back-to-back titles over the Carl Hubbell and Mel Ott-led Giants in 1936 and '37, then swept the Cubs in 1938 and the Reds in '39.
1929: A's defeat Cubs, 4-1
1930: A's defeat Cardinals, 4-2
The A's and Yankees are both the only franchises to win at least three straight World Series, and the only teams to repeat as champions more than once. The A's have done so three times, with the second of those coming from 1929-30 when the team was still in Philadelphia. Those wins over the Cubs and Cardinals marked their final titles under the legendary Connie Mack.
It's no wonder these A's won back-to-back championships. They had a Hall of Fame trio anchoring the lineup -- Jimmie Foxx, Al Simmons and Mickey Cochrane -- and another atop the rotation in Lefty Grove. Foxx hit .344 with 70 homers and 274 RBIs from 1929-30; Simmons hit .373 with 70 homers and 322 RBIs. Cochrane batted .344 between the two seasons. Grove led the Majors in ERA and strikeouts both years, and won pitching's Triple Crown in 1930, going 28-5 with a 2.54 ERA and 209 strikeouts.
1927: Yankees defeat Pirates, 4-0
1928: Yankees defeat Cardinals, 4-0
This was Ruth and Gehrig at their peak, the greatest seasons from two the greatest players in the history of the sport. The 1927 season was Ruth's 60-homer season; in 1928, he hit 54. The Bambino had an incredible 1.215 OPS across the two seasons. Gehrig, meanwhile, was somehow nearly as good. The Iron Horse drove in 173 runs in 1927 and 147 in '28, leading the Majors in RBIs both years. He hit .373 one year and .374 the next, and his combined OPS was 1.179 in that two-season stretch.
There was simply no stopping these Yankees. Both of their World Series wins were sweeps, over the Pirates in 1927 and the Cardinals in '28. Against Pittsburgh, Ruth hit .400 with a pair of homers and a 1.271 OPS, while Gehrig hit .308 with a 1.207 OPS. And against St. Louis, the duo turned in maybe the most dominant World Series hitting performance of all time. Ruth hit .625 with three home runs and a 2.022 OPS over the four games. Gehrig hit .545 with four home runs and a 2.433 OPS.
1921: Giants defeat Yankees, 5-3
1922: Giants defeat Yankees, 4-0-1
These were the first two all-New York World Series. At the dawn of the live-ball era, the small-ball Giants, under John McGraw, beat the slugging Yankees twice in the first Fall Classic meetings of their rivalry. (They would face each other a third straight time in 1923, when the Ruth-led Yankees finally broke through to win the first of the franchise's record 27 World Series.)
All the games in the 1921 and '22 World Series were played at the Polo Grounds, which served as the home ballpark for both clubs at the time -- Yankee Stadium wouldn't open until 1923. Led by a slate of Hall of Famers in Frankie Frisch, Dave Bancroft, Ross Youngs and High Pockets Kelly, the Giants won the 1921 Fall Classic, 5-3, in the last year of the experimental best-of-nine format, before holding the Yankees winless in '22 (Game 2 was a tie, called due to darkness).
1915-16 Red Sox
Red Sox defeat Phillies, 4-1
Red Sox defeat Robins, 4-1
Babe Ruth was still on the Red Sox, and on the mound, for the first two world championships of his career. In 1915, Ruth went 18-8 with a 2.44 ERA as a pitcher, and he went 23-12 with an American League-leading 1.75 ERA and nine shutouts in '16.
The Babe helped lead Boston to consecutive 4-1 World Series wins over the Grover Cleveland Alexander-led Phillies in 1915 and the Brookyn Robins (i.e. the Dodgers) in '16. The first of those years was also Hall of Famer Tris Speaker's final season with the Red Sox, before he jumped to the Indians.
1910: A's defeat Cubs, 4-1
1911: A's defeat Giants, 4-2
The A's 1929-30 World Series titles were their last under Connie Mack; their back-to-back titles in 1910-11, nearly two full decades earlier, were their first under Mack. The A's beat the Mordecai "Three Finger" Brown-led Cubs in five games in 1910 (marking the second year of the Cubs' century-plus-long title drought) and the Christy Mathewson-led Giants in six games in '11.
Philadelphia had its own Hall of Fame ace in Chief Bender, who went 23-5 with a 1.58 ERA in 1910 and 17-5 with a 2.16 ERA in '11. The A's also had Eddie Collins in the lineup, who had a Major League-leading 81 stolen bases in 1910, and Home Run Baker, who appropriately had an AL-leading 11 home runs in 1911.
1907: Cubs defeat Tigers, 4-0-1
1908: Cubs defeat Tigers, 4-1
After this pair of championships, Cubs of course wouldn't win another World Series for 108 years. But the 1907 and '08 Cubs twice bested Tigers teams led by the legendary Ty Cobb to bring home the franchise's first titles and become MLB's first repeat World Series champs.
"Three Finger" Brown led the way on the mound. He went 20-6 with a 1.39 ERA in 1907, and 29-9 with a 1.47 ERA -- while pitching 312 1/3 innings -- in '08. Brown threw a shutout in the clinching Game 5 of the 1907 World Series, and another in Game 4 of the '08 Fall Classic. The 1907-08 Cubs also featured the famed Tinker-to-Evers-to-Chance double play combination.
David Adler is a reporter for MLB.com based in New York. Follow him on Twitter at @_dadler.