Accession to the London Act (1934) by the Federation of Rhodesia and Nyasaland: September 25, 1957; Entry into force: April 1, 1958. Signature of the Lisbon Act (1958): October 31, 1958. Declaration of continued application by Northern Rhodesia: August 26, 1964. Declaration of continued application by the Republic of Zambia: December 31, 1964; Entry into force: April 6, 1965.