Complex sentence: In the 1920s the Third Ward surpassed the Fourth Ward as the center of Houston's African-American community; the Fourth Ward lost prominence due to its inability to expand geographically, as other developments hemmed in the area.
Split into simpler sentences: In the 1920s the Third Ward surpassed the Fourth Ward as the center of Houston's African-American community. The Fourth Ward lost prominence due to its inability to expand geographically, as other developments hemmed in the area.