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 modern in the negative sense. His mode of expression, peculiar and distinctive as it may be, feels quite natural; not for an instant does one get the impression that he sought out new paths simply to get away from the well known roads; the affectation which so often characterizes modern music is not to be found in Carl Nielsen; his thoroughly wholesome musical idiom and his ability to create living music has produced here an organ work of enduring value. Emilius Bangert gave Nielsen’s work a masterly performance..."
Music
In connection with the Lübeck performance, Nielsen was invited to provide programme notes. First explaining in a footnote that Commotio meant "Movement, also spiritual", he continued : "The Latin word Commotio really applies to all music, but the word is used more specifically here as an expression of self-objectification. In a major work for the mighty instrument that is called the organ, whose sound is determined by the natural element we call air, the composer must attempt to suppress all personal, lyrical feelings. The expression becomes great and rigorous and demands a kind of dryness instead of the emotional, and must rather be gazed at with the ear than embraced by the heart. The work is borne up by two fugues, to which an introduction, intervening movements and coda cling like climbing plants to the tree-trunks of the forest; however, the composer thinks that further analysis is superfluous."
