During the First World War, the Polish independence milieus disagreed on geopolitical choices and decided to support different European powers. Roman Dmowski, the leader of the National Democracy (Narodowa Demokracja, ND), wanted to strive for autonomy within the Russian Empire so before the outbreak of the war, he supported the Triple Entente that was the alliance of the Russian Empire, the French Third Republic and Great Britain. In contrast, Józef Piłsudski, the leader of the left-wing independence movement, opted for the Central Powers, fighting alongside Austro-Hungarian Empire.
In November 1914, the National Democracy members with other conservative pro-Russian activists established the Polish National Committee (Komitet Narodowy Polski, KNP) calling for a fight against Germany that was considered one of the greatest enemies of Poland. The committee tried to form the independent Polish army, called the Puławy Legion (Legion Puławski), but the undertaking failed due to the lack of commitment of the Russian authorities that only limited themselves to hasty declarations about the future unification of Polish territories.
The following year, the German offensive led to the occupation of Warsaw. In this situation, the committee members and supporters decided to move to Russia. From 1916, when Russia started to grow weaker, Dmowski believed that it was necessary to focus on the Western allies. Therefore, he launched a campaign in France and Great Britain to restore independence in Poland.
After the February Revolution in Russia, Dmowski and his co-workers and allies established the Polish National Committee on 15 August 1917 in Lausanne. Dmowski became the president, and the members included, among others, the conservative Erazm Piltz or count Maurycy Zamoyski, one of the wealthiest Poles who financed the activities of the organisation. Another important member was the pianist and future Prime Minister of Poland Ignacy Jan Paderewski, who was engaged in the work for the compatriots in the United States.
The Polish National Committee became a body that was recognised by the Entente as a political partner and representative of the Poles in international affairs. On the committee’s initiative, the Polish Army, also called the Blue Army because of the colour of the uniforms, was formed in France. It included about 100,000 soldiers and was directed by General Józef Haller. In the autumn of 1918, through the agency of the committee, Chief of State Piłsudski earned international recognition for the state that was being restored. Moreover, the committee members, along with the representatives of the government in Warsaw formed the Polish delegation that was sent to the Peace Conference held in Paris in 1919.