How did misty copeland make american ballet theatre history?

On June 30, 2015, Copeland became the first African American woman to be promoted to principal dancer in ABT's 75-year history. After two summer workshops with ABT, she became a member of ABT's Studio Company in 2000 and its corps de ballet in 2001, and became an ABT soloist in 2007.
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The period that marks the paleolithic era is between the 250,000 to 10,000 years.