Oldenburg (state)
At first vassals of the Welf Saxon prince Henry the Lion, they took advantage of his deposition by Emperor Barbarossa to make themselves autonomous.
The Lordship of Jever was willed by Anthony Günther, Count of Oldenburg to the Principality of Anhalt-Zerbst and in 1795 fell by Kunkellehen (female inheritance) to the Russian empress Catherine the Great.
[citation needed] Through a territorial trade, the County of Oldenburg was assigned in the Treaty of Tsarskoye Selo on the 27th of August, 1773, to the head of the House of Holstein-Gottorp, the future Emperor Paul I of Russia, who four days later transferred the country to his cousin Frederick August, the Prince-bishop of Lübeck, who was then promoted by Emperor Joseph II to the rank of duke in 1774/1777.
The duchy thus consisted of two geographically separate parts: Oldenburg proper and the Prince-bishopric of Lübeck with the Residenz of Eutin.
In the Reichsdeputationshauptschluss of 1803 Oldenburg obtained the Hanoverian district of Wildeshausen and the districts of Vechta and Cloppenburg from the dissolved Prince-Bishopric of Münster in compensation for losing the Elsfleth Weser Toll (ship toll on the Weser levied by Oldenburg 1623 - 1820).
The Duke fled to his son George in Russia, who had married the Emperor's daughter Catherine Pavlovna.
In 1814, after the fall of Napoleon, the Duke returned to his country, which was raised to a grand duchy in 1815 after the Congress of Vienna.
Furthermore, Oldenburg received a new exclave, the Principality of Birkenfeld on the Nahe, so that the national territory now comprised three parts.
On the 28th of February, 1849, in the context of the German Revolution, the Fundamental Law of the State, the first Oldenburgish constitution, came into force.
Hanover joined the Deutscher Zollverein (German Customs Union) in 1854, after negotiating advantageous conditions with Prussia and, facing isolation, Oldenburg followed suit the same year.
In the Austro-Prussian War of 1866 Oldenburgish troops fought on the side of Prussia against Austria, joining the Prussian dominated North German Confederation in 1867.
In non-binding referendums in 1956 and on 19 January 1975, citizens in Oldenburg voted to become a separate state from Lower Saxony.
