The term Treaty of Berlin is often used for the agreement of April 24, 1926 under which Germany and the Soviet Union each pledged neutrality in the event of an attack on the other by a third party. Occasioned by Soviet fears of Germany's rappochement with Britain and France in the 1925 Locarno Treaties, the pact reaffirmed on paper the German-Soviet diplomatic understanding reached in the 1922 Treaty of Rapallo, but relations between the two powers cooled despite its renewal in 1931 and 1933.