The artistic and practical value of his work was the subject of much debate after German reunification. Under the 1971 Four Power Agreement on Berlin, Berlin was formally outside the bounds of either East or West Germany, and so the West German parliament, the "Bundestag", was not allowed to assemble formally in West Berlin. This prohibition was obeyed even though East Germany had declared East Berlin its capital, violating this provision. Until 1990, the building was thus used only for occasional representative meetings, and one-off events, such as a free concert given by British rock band Barclay James Harvest on 30 August 1980. It was also used for a widely lauded permanent exhibition about German history called "Fragen an die deutsche Geschichte" ("Questions to the German history").