Complex sentence: He was also the 1917 winner of the NAACP's Spingarn Medal, which is awarded annually by the National Association for the Advancement of Colored People (NAACP) for outstanding achievement by an African American.
Split into simpler sentences: He was also the 1917 winner of the NAACP's Spingarn Medal. The Spingarn Medal is awarded annually by the National Association for the Advancement of Colored People (NAACP) for outstanding achievement by an African American.