Recognition began on December 2, 1829, when U.S. Secretary of State
Martin Van Buren issued an exequatur to
Frederick A. Mensch Esq. as Consul for
Augustus, Grand Duke of Oldenburg at New York. On March 10, 1847, the United States and the Grand Duchy of Oldenburg signed the Declaration of Accession to the Treaty of Commerce and Navigation with
Hanover, to regulate trade, commerce, and navigation between the U.S. and Oldenburg. The declaration was signed by U.S. Special Agent
Ambrose Dudley Mann and Oldenburg’s head of Foreign Affairs,
W.E. de Beaulieu Marconnay. On December 30, 1853, the Grand Duchy of Oldenburg signed the Declaration of Accession to the Convention for the Extradition of Criminals, Fugitives from Justice, of June 16, 1852, Between the United States and Prussia and other states of the
German Confederation, to establish reciprocal extradition of fugitive criminals in special cases. In 1867, the grand duchy joined the
North German Confederation as a result of the
Austro-Prussian War and continued relations under the Confederation. Relations further continued when it joined with the
German Empire in 1871, but ended with the outbreak of the First World War and the American declaration of war against Germany. ==See also==