The Boston Red Sox are a Major League Baseball team and a member of the American League East Division. The Red Sox are one of the eight American League charter teams, joining the league in 1901. The team had a lot of success early on, winning five World Series titles from 1903 until 1918. However, the franchise had to wait 86 years until the next championship. Their main rival is the New York Yankees. Ted Williams and Carl Yastrzemski are considered the best players to ever put on a Red Sox uniform.