Complex sentence: The 20th century American composer Charles Ives used the Camp Meeting phenomenon as a metaphysical basis for his Symphony No.3 (Ives) and hymn tunes and (closely related) American Civil War area popular songs as part of the symphony's musical material.
Split into simpler sentences: The 20th century American composer Charles Ives used the Camp Meeting phenomenon as a metaphysical basis for his Symphony No.3 (Ives). Hymn tunes and American Civil War area popular songs (which are closely related to camp meeting songs) as part of the symphony's musical material.