World War I smashed the empires of Austria-Hungary, Germany and Russia, which allowed Poland to re-emerge as an independent state. When the German and Austrian armies overran Russian Poland in 1916, the foundations of a Polish kingdom and the restoration of the Polish language were carried out cynically by an interim administration, known as the Regency Council. Two bitter rivals had emerged as potential leaders of the new Polish nation: Józef Piłsudski and Roman Dmowski.
Józef Piłsudski aimed for a military solution to Poland's troubles. During World War I, his armies fought on behalf of the Germans, assuming that the defeat of the Russians would allow him to create the new state of Poland on his own terms. In this, he favoured a return to the great tradition of ethnic and religious diversity of the former Polish-Lithuanian Commonwealth. Roman Dmowski was the leader of the Nationalist League. His ambition was to form a new middle class in a purely Polish and Catholic future in which the Jews would be excluded. He opted for independence by means of political ways. He hoped that a Polish victory over the Germans would allow the western allies to set up a new Polish state under his leadership.
Józef Piłsudski came out on top. The Germans had held him prisoner until one day before the armistice of 11 November 1918. This allowed him to take command of the Regency Council and became head of state three days later.