Federalist ideas, which sought to reduce State sovereignty, were debated between 27 and 31 August 1947 at the first Union of European Federalists (UEF) Congress, held in Montreux, Switzerland. The participation of eminent persons and numerous delegations demonstrated the interest in federalist ideas. 16 countries were represented in Montreux, together with some 40 activist groups. The Montreux Congress also served to reaffirm the principle of regional federalism in contrast to the internationalist arguments very fashionable at that time. The general policy motion adopted by the Congress called for the creation of a European federal government. The participants also urged the convening of a mass event involving all the forces active in Europe. Less than a year later, this took the form of The Hague Congress.