The National Union of the Unions of the Workers of Benin (UNSTB) was, from its founding in 1974 until the 1990s, the sole union federation in Benin. It was originally closely related with the People's Revolutionary Party of Benin (PRPB). The UNSTB is affiliated with the International Trade Union Confederation. The People's Revolutionary Party of Benin (French: Parti de la Révolution Populaire du Bénin) was a political party in Benin. It was founded in 1975 by General Mathieu Kérékou. With the new constitution of November 30, 1975, PRPB became the sole legal party in the country.