Sanation appeared prior to the May 1926 "Coup d'État" and lasted until World War II but was never formalized. Piłsudski, though he had been the former leader of the Polish Socialist Party, had grown to disapprove of political parties, which he saw as promoting their own interests rather than supporting the state and the people. For this reason, the Sanation movement never led to the creation of a political party. Instead, in 1928 Sanation members created a "Bezpartyjny Blok Współpracy z Rządem" ("Nonpartisan Bloc for Cooperation with the Government"), a pro-government grouping that denied being a political party.