The Baltimore Orioles are an American professional baseball team based in Baltimore, Maryland. The Orioles compete in Major League Baseball (MLB) as a member club of the American League (AL) East division. As one of the AL's original eight charter franchises when the league was established in 1901, this particular franchise spent its first year as a major league club in Milwaukee, Wisconsin, as the Milwaukee Brewers before moving to St. Louis, Missouri, to become the St. Louis Browns. After 52 often-beleaguered years in St. Louis, the franchise was purchased in November 1953 by a syndicate of Baltimore business and civic interests led by attorney/civic activist Clarence Miles and Mayor Thomas D'Alesandro Jr. The team's current majority owner is lawyer Peter Angelos.
The Orioles adopted their team name in honor of the official state bird of Maryland; it had also been used by several previous major and minor league baseball clubs in Baltimore, including the team that moved and was later renamed the New York Yankees. Nicknames for the team include the "O's" and the "Birds".
The Orioles experienced their greatest success from 1966 to 1983, when they made six World Series appearances, winning three of them (1966, 1970, 1983). This era saw the club feature several future Hall of Famers who would later be inducted representing the Orioles, such as third baseman Brooks Robinson, outfielder Frank Robinson, starting pitcher Jim Palmer, first baseman Eddie Murray, shortstop Cal Ripken Jr., and manager Earl Weaver. The Orioles have won a total of nine division championships (1969–1971, 1973–1974, 1979, 1983, 1997, 2014), six pennants (1966, 1969–1971, 1979, 1983), and three wild card berths (1996, 2012, 2016).
After suffering a stretch of 14 straight losing seasons from 1998 to 2011, the team has qualified for the postseason three times since 2012 under manager Buck Showalter, including a division title and advancement to the American League Championship Series for the first time in 17 years in 2014.
The Orioles are also well-known for their influential ballpark, Oriole Park at Camden Yards, which opened in 1992 in downtown Baltimore.