The first musical victim of the events in Germany was the opera, Die Beiden Klaas (op. 42). This work appeared to have been pursued by the irony of fate with particular doggedness. It was completed in 1933, when Gál was at his height, and the most important opera houses competed for the first performance. A double premiere was planned, with simultaneous first performances in Hamburg and Dresden, which would have taken place in 1933 had they not fallen victim to the political circumstances. The work was then proposed for performance by Bruno Walter at the Vienna State Opera, but the directors had reservations: the opera was offensive and could undermine public morals - clear precursors of the Nazi persecution of 'degenerate' art. It was nevertheless accepted by the Vienna Volksoper and was in preparation at the beginning of 1938, but was then abandoned when the Volksoper suffered a financial collapse - shortly before the National Socialists 'annexed' Austria to Germany. It was eventually given its first posthumous performance in York, England (in English translation), 57 years later to mark the 100th birthday of the composer, and without any catastrophes.

The work - it is a numbers-opera in the style of the German 'Singspiel' - is based on the Low German version of the mediaeval farce which underlies Hans Christian Andersen's tale of Big Claus and Little Claus, and again it arose in close collaboration with Levetzow. The text of the story is, however, woven together with other freely invented themes into a timeless yet at the same time contemporary satire against sexual hypocrisy and petty-bourgeois 'morality'. In the character of the Midwife, who is stylised beyond the traditional match-maker/gossip into a kind a surrealist 'Führer' figure, with her retinue of grotesquely comic petty-bourgeois neighbours - the self-styled 'Furies of Morality' - one can draw some parallels with the street politics of the later Weimar republic. One senses above all in this opera the sharp satirical humour of Levetzow who (with Wolzogen) was director of the Munich Cabaret 'Die Elf Scharfrichter' ('The Eleven Executioners'), but the bitter and sceptical basis is completely absorbed into a coarse, popular humour and a correspondingly cheerful and humorous music.