He was born in Ruszki near Kutno on 17 August 1877. He belonged to the Polish Socialist Party, and to the Polish Socialist Party – Revolutionary Faction after it had split. He was a close collaborator of Józef Piłsudski (among others, he wrote his speeches). During World War I, he became involved in the work of the Polish National Organisation and also headed the Central National Committee (1915–1916). In 1917, he became the secretary of the Provisional Council of State. After Poland had regained independence, he remained politically active, initially as the deputy chair of the Warsaw City Council and Vice-Mayor of Warsaw (1919–1922). In 1922, he was Prime Minister for a few days between his appointment on 28 June and resignation on 7 July. From 1935 to 1938, he sat in the Senate of the Republic of Poland. He was deputy chair of the Polish Writers’ Union. During World War II, he was active in the Warsaw Civic Committee and the Warsaw Self-Help Committee. He died on 16 January 1953 in Warsaw. Most important works: Hetman Żółkiewski (1920), Jan Sobieski (1924), Maurycy Mochnacki (1910), Mickiewicz jako polityk [“Mickiewicz as politician”] (1908), Na przełomie dwóch epok [“Between two epochs”] (1931), Powstanie kościuszkowskie [“Kościuszko Uprising”] (1917), Polska niepodległa [“Independent Poland”](1919), Powstanie listopadowe [“November Uprising”] (1911), Powstanie Styczniowe [“January Uprising”] (1919), Stefan Batory (1922), Warszawa w czasie najazdu bolszewickiego [“Warsaw during the Bolshevik invasion”] (1928).