St. Louis Bombers Team Portrait 1945.
St. Louis Bombers pose for a team portrait circa 1945 in St. Louis, Mo.NBA Photos/NBAE—Getty Images
St. Louis Bombers Team Portrait 1945.
Bob Davies of the Rochester Royals poses for an action portrait during the 1946 season in Rochester, New York.
Angelo Musi of the Philadelphia Warriors poses for a portrait circa 1947 at the Philadelphia Civic Center in Philadelphia, Pennsylvania.
St. Louis Bombers Team Portrait 1947.
Red Rocha (4), St. Louis Bombers center, goes up in the air to make a pass in Basketball Association of America playoff game with the Philadelphia Warriors at the Arena, March 30, 1948. Chuck Halbert, lanky Warriors center, also leaves the floor in an attempt to block the pass.
Minneapolis Lakers teammates congratulate George Milken after the 6-foot 10-inch wizard racked up 48 points in a 101-74 victory against the New York Knicks at Madison Square Garden. Feb. 23, 1949.
NBA and NBL Merge 1949
Harry Gallatin #11 and Nathaniel Clifton #8 of the New York Knicks pose for portrait circa 1950 in New York, New York.
Earl Lloyd #11 of the Syracuse Nationals poses for a portrait circa 1950.
Bob Cousy #14 of the Boston Celtics drives to the basket against Dick McGuire #15 of the New York Knicks at the Boston Garden circa 1950 in Boston, Massachusetts.
George Mikan (99), star Minneapolis Lakers center, breaks up a shot by Bob Davies, Rochester Royals guard (11) in the decisive game of the National Basketball Association's Western Division playoffs, April 4, 1951 in Rochester, N.Y. Rochester, won, 80-75.
Minneapolis Lakers v Philadelphia Warriors 1951
Minneapolis Lakers hoist coach John Kundla and carry him to their dressing room after beating the New York Knickebockers 82-65 April 25, 1952, and winning their fourth National Basketball Association title in five years.
Bob Cousy (14) of the Boston Celtics takes a rebound off the backboard after an attempted basket by Dick McGuire (15) of the New York Knickerbockers in the fourth quarter of their NBA playoff game at the Boston Garden in Boston, Mass., March 26, 1953.
Kentucky basketball coach Adolph Rupp talks to players, from left, Cliff Hagan, Lou Tsioropoulos and Frank Ramsey (30) in Lexington, Ky. Circa 1954.
Bob Pettit of the St. Louis Hawks poses for a portrait with referees circa 1955.
Boston Celtics - New York Knicks 1955
Philadelphia Warriors against the Fort Wayne Pistons during Game Five of the NBA Finals on April 7, 1956 at the Philadelphia Civic Center in Philadelphia, Pennsylvania. The Philadelphia Warriors defeated the Fort Wayne Pistons 99-88 and won the series 4-1.
St. Louis Bombers pose for a team portrait circa 1945 in St. Louis, Mo.
NBA Photos/NBAE—Getty Images
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See Photos From the NBA's Early Years

It was 70 years ago—on June 6, 1946—that the original NBA team owners met in New York City and changed the history of American pro basketball, establishing two divisions with 11 teams total. The organization they founded (then called the Basketball Association of America) was the product of their professional interest in filling arenas, according to the NBA Encyclopedia, not in the sport itself. After all, many of them owned the venues too. The first season would begin that autumn.

The BAA wasn't the first basketball league to be formed, and it had competition in the form of the National Basketball League. But NBL games tended to take place in small venues, as described by Michael Schumacher's Mr. Basketball, and the league wasn't really successful as a big business. Even though the BAA founders weren't the biggest hoops fans in the world, they knew how to make the league a success. So it's perhaps no surprise that, though the BAA and NBL merged in 1949 to become the National Basketball Association, the NBA still counts that 1946 day as its founding date.

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TIME reported in 1949 that "pro basketball is gradually taking on a big-league glow. The Basketball Association of America is a twelve-city circuit, playing to enthusiastic crowds from Manhattan's Madison Square Garden to St. Louis' Arena. Its stars get paid as much as $17,500 for a 20-week season."

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