"In 1918 the Red Sox won their 5th World Series, the most by any club at that time. One of the stars of the Boston championship franchise was a young pitcher by the name of George Herman Ruth, aka The Babe or The Bambino.
In 1920, however, Red Sox owner Harry Frazee needed money to finance his girlfriend's play, so he sold Babe Ruth's contract to Colonel Jacob Ruppert's New York Yankees for $100,000 (plus a loan collateralized by Fenway Park).
Since then, the Yankees, who had never won a World Championship before acquiring Ruth, have gone on to win 26, and are arguably one of the greatest success stories in the history of sport.
Meanwhile, the Boston Red Sox have appeared in only four World Series since 1918, losing each one in game seven. Many consider Boston's performance after the departure of Babe Ruth to be attributable to "The Curse of the Bambino."
Bambino's Curse: Diary of a Red Sox Fan