These twin brothers are the stars of Rome's most popular foundation myth. Children of Mars (the Roman god of war) and Princess Rhea Silvia (a Vestal Virgin), Romulus and Remus were abandoned as infants by the river Tiber and nursed by a she-wolf. A shepherd and his wife raised the pair, but once they discovered their true heritage the brothers reclaimed power and established a new city. But the brothers quarreled over the location of the site and Romulus killed Remus to found Rome (named for himself) on the Palatine Hill.
In the Book of Genesis, Cain and Abel are the sons of Adam and Eve. Cain is a farmer, and his younger brother Abel is a shepherd. Both boys proceed to make offerings of their production to God. But when Abel's is accepted and Cain's is denied, Cain takes his brother into the field and kills him. Lucky for the Harbaugh brothers, the "field" at the Superdome is a bit more public.
Also in the Book of Genesis, the intense sibling rivalry of Leah and Rachel gives meaning to the phrase "biblical proportion." Jacob falls in love with Rachel, the younger sister, but on their wedding night her father, Laban puts Leah in her place. This trick leaves Jacob with two extremely irritated wives, and the two sisters with a lifetime of competition.
Edgar and Edmund are the two sons of the Earl of Gloucester in Shakespeare's Tragedy of King Lear. Edgar is the legitimate heir to the earldom while Edmund was born out of wedlock and thus has no right to his father's lands. Overcome with jealousy, Edmund plots to kill his brother and steal his title. Edgar hears of the scheme in time to disguise himself as a beggar named Poor Tom, and escapes into the wilderness.
Pauline Esther Friedman is the maiden name of Dear Abby columnist Pauline Phillips, author of the nationally syndicated advice column. Esther Pauline Freidman is the maiden name of her identical twin sister, author of Ask Ann Landers a similarly popular advice column. Both sisters began their long and extremely successful careers in the 1950s, and though their columns rivaled each other, it's hard to imagine that these wise sages ever fought.
The Williams sisters have tennis in their blood. Both of these prodigies have been ranked No. 1 in the world in women's singles. Venus Williams holds seven Grand Slam titles, and her younger sister, Serena Williams holds 30. Though these two have fought each other tirelessly on the court, their sibling rivalry has always ended when they reach the sideline.