Complex sentence: A highly significant factor in his musical development was the English folksong revival, evident in the orchestral suite "A Somerset Rhapsody" (1906--07), a work that was originally to be based around eleven folksong themes; this was later reduced to four.
Split into simpler sentences: A highly significant factor in his musical development was the English folksong revival. The folk influence was evident in the orchestral suite "A Somerset Rhapsody" (1906--07), a work that was originally to be based around eleven folksong themes; this was later reduced to four.