Complex sentence: The DuSable Museum quickly filled a void caused by limited cultural resources then available to African Americans in Chicago and became an educational resource for African American history and culture as well as a focal point in Chicago for black social activism.
Split into simpler sentences: The DuSable Museum quickly filled a void caused by limited cultural resources then available to African Americans in Chicago and became an educational resource for African American history and culture. It also became a focal point in Chicago for black social activism.