The Boston Americans became a professional baseball team in 1901. They later changed their name to the Boston Redsox in 1908. In 1912 the Redsox built their baseball field Fenway Park, which they still play in today. Over the Redsox 109 years as a professional baseball team, they have won seven World Series championships. They won the World Series in 1903, 1912, 1915, 1916, 1918, 2004, and 2007. The 86 years in between the World Series championships was known as "The Curse of the Bambino". The Bambino was a nick-name for Babe Ruth, who the Redsox traded after their 1918 World Series win. The Redsox have retired the numbers of six players, Bobby Doerr, Joe Cronin, Johnny Pesky, Carl Yastrzemski, Ted Williams, and Carlton Fisk.