The creation of professional basketball teams (1930s)

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(The new York Celtics)

In the 1930s early teams such as the new York Celtics were created who brought new innovations to the game such as player contracts, due to the fact that back in those days players were just switching from team to team depending on who payed them the most. Back in those days there wasn't a set league that everybody played in, there were multiple leagues around the country.