Two commemorative coins were issued by the Central Bank of Ceylon in April 1957 for the 2500th anniversary of the cannonical year for the passing away of Buddha and the Birth of the nation. An one rupee cupro-nickel coin was issued for circulation together with a five rupee crown-sized silver coin. Source: 1957 - Sri Lanka - Buddha Jayanthi - 1 Rupee (lakdiva.org)