Complex sentence: Nielsen finished the whole symphony on 15 January 1922 as dated on the score, only nine days before its première at the music society Musikforening in Copenhagen, conducted by the composer himself.
Split into simpler sentences: Nielsen finished the whole symphony on 15 January 1922 as dated on the score. The première took place only nine days after, at the music society Musikforening in Copenhagen, conducted by the composer himself.