"The Prince of Hamburg", which was staged at the "Royal Theater", is Klais's most ambitious work. It is a matter of debate whether there exists in world literature a patriotic work that is so deeply human. The tragic struggle between duty and affection that takes place within the soul of the Elector, and the even more tragic ambivalence of the heroic prince between the death imposed on him by the relentless military law and the life that calls him with benevolent selflessness into its embrace, create an atmosphere in the work that is so warm, where even this admittedly rare patriotic rigor of the heroes of Ferbellin takes on the internal density and plastic weight of life transformed into art. [...] There is no purposefulness anywhere in Klais's work. There is only poetry, pure poetry, which alone creates truth and life in art. (Leon Koukoulas)