The International Agrarian Bureau was founded in 1921 by the Agrarian parties of Bulgaria, Czechoslovakia, Croatia, and Poland, growing to 17 political parties in Eastern Europe by 1928. It was sometimes referred to as the "first Green International". The Bureau was a key competitor with the Red Peasant International sponsored by the Communist International or Comintern. In 1947, the Bureau assumed the name of the International Peasants' Union. Stanisław Mikołajczyk was the president of the organization at one point.