Carl Nielsen's Commotio or Commotio for Organ, Opus 58, was composed between June 1930 and February 1931. The composer's last major work, it was first performed privately on 24 April 1931 in the chapel at Christiansborg Palace in Copenhagen. Background Commotio was considered by Nielsen to be a particularly important work. In a letter to his son-in-law Emil Telmányi on 24 February 1931 he wrote: "None of my other works has demanded such great concentration as this: an attempt to reconstitute what is truly the only valid organ style, the polyphonic music that is especially suited to this instrument, which for a long time has been regarded as a kind of orchestra, which it absolutely is not." Nielsen also commented on the length of the piece: at 22 to 24 minutes, it was longer than any of Bach's organ works. There was great interest in the piece by Danish organists, resulting in several private performances. In addition to that at the Christiansborg Palace Chapel, there were two performances by Peter Thomsen, two by Finn Viderø on 14 June on the Marcussen organ in St Nikolai's Church, Copenhagen, one a week later by Emilius Bangert in Roskilde Cathedral and yet one more by Peter Thomsen in July. Reception The first public performance was in Aarhus Cathedral on 14 August 1931 where the organist was Emilius Bangert. Despite poor health due to heart problems, Nielsen was present. There do not appear to be any reviews of this performance. After news of the new organ work reached Germany, Erwin Zillinger, an organist from Schleswig, asked Bangert and Nielsen whether Commotio could be played at the Nordic-German Organ Week to be held in Lübeck that October. Nielsen had hoped to be present but weakness resulting from poor health prevented him from travelling. Bangert. who had been selected as the organist, travelled alone to Lübeck where, a day or two later, he heard of Nielsen's death. The concert therefore suddenly became a valedictory performance. The review by Svend-Ove Møller in Dansk Kirkemusiker-Tidende conveyed the emotional experience: “Mixed with the melancholy feelings that fill us on the death of Nielsen, is gratitude that it was granted him to complete this work, which we may designate without exaggeration as the most significant production in recent organ literature. Nielsen understood as few others did how to deploy the resources of his time such that they do not appear