|Jim and John Harbaugh|
For the first time in professional football history, a pair of brothers will lead the teams playing at the Super Bowl. John Harbaugh, 50, head coach of the Baltimore Ravens, will face off against younger brother Jim Harbaugh, 49, skipper of the San Francisco 49ers, at this year's Super Bowl in New Orleans.
The men, just 15 months apart, grew up in Ann Arbor, Mich., and both began their coaching careers working for their father Jack, a college coach at Western Kentucky and later at Western Michigan. The brothers are close and consider the matchup, already dubbed by sportswriters as the "HarBowl" a bittersweet moment for the family, knowing one will lose.
The Harbaughs will take to the biggest stage in sports to duke things out on Feb. 3. And while their faceoff is the rivalry of the season, it's far from the first of its kind.
|Venus and Serena Williams|
Venus Williams, 32, and sister Serena Williams, 31, have been at the top the women's tennis leader boards for more than a decade. They have each been ranked the No.1 player in the world, and twice were ranked No. 1 and No. 2. The sisters, who grew up in Compton, Calif., and were coached together by their father Richard Williams, have met on the court to battle for a title at eight Grand Slam tournaments. Currently, Serena holds more titles, 45 of them to Venus's 44.
|Ann Landers and Dear Abby|
Dueling columns "Dear Abby" and "Ask Ann Landers," have meted out advice to thousands of newspaper readers for more than five decades. The women behind the columns were identical sisters, whose rivalry was so bitter they did not speak to each other for many years. Esther Lederer took over the Ann Landers advice column at the Chicago Sun-Times in 1955. Her sister Pauline Philips, writing under the penname Abigail Van Buren, launched a competing column "Dear Abby," the following year. Lederer, who died at 83, stopped writing her column in 2002. Philips died last week; she was 94.
|Peyton and Eli Manning|
Peyton Manning, 36, and younger brother Eli, 32, are both members of an elite group of pro football quarterbacks and have faced off on the field several times. Eli, the QB for the New York Giants, has earned two Super Bowl rings, one in 2008 and 2012. Peyton, formerly of the Indianapolis Colts and now quarterback for the Denver Broncos, won a Super Bowl in 2011.
|Cain and Abel|
The original sibling rivalry, between Cain and Abel, the descendents of the Bible's Adam and Eve did not end well. Cain is described in the Book of Genesis as a farmer, and his younger brother Abel a shepherd. By most interpretations, Cain was driven to murder by jealousy. Cain is by tradition considered the first murderer and Abel, the first person to be killed.
|Adolf and Rudolf Dassler|
Adolf and Rudolf Dassler, were German brothers whose rivalry spawned two of the world's largest sports merchandise companies. The two brothers, and Nazi sympathizers, worked together at Adidas, founded by Adolf, through much of World War II. However, a dispute in a bomb shelter during an Allied bombing, led to an insurmountable rift, and Rudolf leaving to found his own company, Puma.