 Complete the following phrase:  After the First World War, a plebiscite was held on 20 March 1921 under the terms of the Treaty of Versailles to determine whether the parts of Silesia which had belonged to Prussia and thus to the German Empire would remain German or join the reconstituted Poland. In the parish of Annaberg, as in most of Upper Silesia, a majority voted for Germany, but the local administrative district Landkreis Groß Strehlitz was one of the areas where the majority favoured union with Poland. In early May the Third Silesian Uprising began, with Polish units of the Wawelberg Group, against the wishes of the Polish government, seeking to unite with Poland those areas that had voted for it. On 4 May they captured the Annaberg, which in addition to the cultural importance of the monastery for German Silesians, had strategic importance since it dominates the Oder valley, from the legally limited forces of the German army. On 2123 May, in the 