Born in 1898, the German playwright and poet Brecht is one of the seminal figures of twentieth century drama. Essentially, he viewed theater, and the arts in general, as a means of advancing revolutionary ideas which would contribute to the elimination of political oppression and social injustice. An exceptionally innovative writer, Brecht, whose earliest plays were realistic, embraced expressionism, exemplified by his 1926 play Mann ist Mann (Man is Man). Having formulated an original conception of theater, known as epic theater, which questioned the idea of art as an illusion, Brecht strove to enlighten the spectator by manipulating dramatic devices and stage techniques. According to Brecht, who detested capitalism and its social institutions, enlightened meant the realization that society, which is unjust, needs to undergo a revolutionary transformation. Brecht's writings attracted composers, particularly Kurt Weill, who, sharing Brecht's conviction that the purpose of art is social change, became famous for his works based on Brecht's texts. Best known among the works created by Brecht and Weil is Die Dreigroschenoper (The Threepenny Opera), based on the libretto of John Gay's The Beggar's Opera (1728). In this eclectic work, a mosaic of various musical traditions, including jazz and popular song, what comes to the fore as a remarkable artistic achievement are the songs, in which Brecht's brilliantly expressed cynicism and Weill's haunting, ironic, but eminently accessible music blend to create a powerful, almost hallucinatory, parody of capitalist society, which the poet and the composer condemned as profoundly corrupt. Another famous collaborative work is Aufstieg und Fall der Stadt Mahagonny (Rise and Fall of the City of Mahagonny), which describes, in nightmarish detail, the decay and ultimate downfall of a pleasure-loving community existing outside the realm of ethics, justice, and common sense. Brecht left Germany in 1933, as the newly elected Nazi regarded him as a decadent artist who should not be allowed to work. He first lived in Denmark, later moving to in the United States. In the 1940s, Brecht wrote two extraordinary plays, Mutter Courage und ihre Kinder (Mother Courage and Her Children) and Der gute Mensch von Sezuan (The Good Woman of Setzuan), which explore ethical issues. Der Kaukasische Kreidekreis (1948) is considered Brecht's greatest epic play. In 1948, Brecht established himself in East Berlin, which in 1949 became the capital of East Germany. As a Marxist playwright, he enjoyed great prestige in East Berlin. Deeply involved, as director of the acclaimed Berliner Ensemble, in East German cultural life, he remained active until his death in 1956.