Oldenburg (355), a German grand-duchy, embracing these three territories: 1, Oldenburg proper, the largest, is let into Hanover with its northern limit on the North Sea; it is a tract of moorland, sand-down, and fen, watered by the Weser, Hunte and tributaries of the Ems; here is the capital, Oldenburg (22), on the Hunte, 30 m. NW. of Bremen, in the midst of meadows, where a famous breed of horses is raised. 2, Lübeck, lying in Holstein, N. of but not including the city of Lübeck. 3, Birkenfeldt, lying among the Hundsrück Mountains, in the S. of Rhenish Prussia; independent since 1180, Danish 1667-1773, Oldenburg acquired Lübeck in 1803, and Birkenfeldt in 1815, when it was raised to the rank of grand-duchy.