The Treaty of Berlin (German-Soviet Neutrality and Nonaggression Pact) was a treaty signed on 24 April 1926 under which Germany and the Soviet Union pledged neutrality in the event of an attack on the other by a third party for five years. The treaty reaffirmed the German-Soviet Treaty of Rapallo (1922).Ratifications for the treaty were exchanged in Berlin on 29 June 1926, and it went into effect on the same day. The treaty was registered in League of Nations Treaty Series on 3 August 1926. It was renewed by additional protocol signed on 24 June 1931, ratified on 5 May 1933. The additional protocol was registered in League of Nations Treaty Series on 15 February 1935.