The previously-used official names in German  and Russian ''Revel'' () were replaced after Estonia became independent in 1918. At first, both forms ''Tallinna'' and ''Tallinn'' were used. The United States Board on Geographic Names adopted the form Tallinn between June 1923 and June 1927. ''Tallinna'' in Estonian denotes the genitive case of the name, as in ''Tallinna Sadam'' ('the Port of Tallinn').