Nielsen's work on Klavermusik for smaa og store is first mentioned in August 1929 when he was engaged with the question of music for teaching purposes. This is also evident from an introductory address that he gave at the Musikpædagogisk Forening in December 1929. According to his diary, the last fourteen pieces were composed during January 1930 at a rate of roughly one piece a day. See more about this work at The Royal Library