Complex sentence: W.E.B. DuBois, whom he'd known at Harvard, and the followers of Booker T. Washington, and helped ultimately realize the concept of a unified black movement through the founding of the NAACP, the National Association for the Advancement of Colored People.
Split into simpler sentences: W.E.B. DuBois, whom he'd known at Harvard, and the followers of Booker T. Washington. He helped realize the concept of a unified black movement through the founding of the NAACP, the National Association for the Advancement of Colored People.