Empire means
            1) A political unit having an extensive territory or compromising a number of territories or nations and ruled by a single supreme authority.
 

            2) An extensive enterprise under a central authority: a publishing empire.
 

            3) Imperial sovereignty, domination, or control

      When Shirley Hill Witt wrote about the empires, she was talking about the spaniards taking over the empires and Acoma. When they took over the empires, they plundered, looted, and raped the men and woman of every  they were in search for the seven cities of gold.
 

Source: The American Heritage Dictionary
 And
Why We Study American History
        by: Herman J. Viola