The original Royal Rooters were a fan club for the Boston Red Sox in the early 20th century. They were led by Michael T. McGreevy, who owned a Boston saloon called "3rd Base". While M.T. "Nuf Ced" McGreevy was certainly the spiritual (in both libations and foundations) leader of the Royal Rooters, John F. Fitzgerald, the maternal grandfather of John F. Kennedy, served as chairman for a while, and during that time, M.J. Regan was the secretary. Other members included C.J. Lavis, L. Watson, T. S. Dooley, J. Kennan, and W. Cahill, among others. Their theme song was "Tessie" from the Broadway musical "The Silver Slipper". Though the musical ran for less than six months, the song has gone down in history. The Rooters sang "Tessie" at games to encourage their Sox, while simultaneously distracting and frustrating the other team. They were especially important in the first World Series, in 1903, when the Red Sox played the Pittsburgh Pirates. The Royal Rooters would go to Pittsburgh and sing Tessie to distract the opposing players, especially Honus Wagner. Therefore, after falling into a 1-3 deficit, Boston rallied to win the Series with four straight victories. The original Rooters disbanded in 1918.
Their spirit lives on via the current version of the Royal Rooters represented within a group known as Royal Rooters of Red Sox Nation. The current Rooters are based in the Boston area and meet informally for Red Sox games as well as for "outings" in various locations around the country. There is a fairly large contingent in New York City, and their base has been the Riviera Café (known as "The Riv") in the West Village.
The current Rooters keep in touch most often through a dedicated website, Redsoxnation.net. The combination message board, fan forum, and blog has several thousand members.
The band Dropkick Murphys released a re-working of "Tessie" in 2004. Their version became the official song of the Boston Red Sox 2004 World Series run and the band was able to share in the experience of the Red Sox winning the World Series championship. Their version of "Tessie" is still sung widely throughout Red Sox games and in Red Sox Nation.