Saxe-Weimar-Eisenach (German: Sachsen-Weimar-Eisenach) was created as a duchy in 1809 by the merger of the Ernestine duchies of Saxe-Weimar and Saxe-Eisenach, which had been in personal union since 1741. It was raised to a grand duchy in 1815 by resolution of the Vienna Congress. In 1903, it officially changed its name to the Grand Duchy of Saxony (German: Großherzogtum Sachsen), but this name was rarely used. The Grand Duchy came to an end in the German Revolution of 1918-19 with the other monarchies of the German Empire. It was succeeded by the Free State of Saxe-Weimar-Eisenach, which was merged into the new state of Thuringia two years later.
The full grand ducal style was Grand Duke of Saxe-Weimar-Eisenach, Landgrave in Thuringia, Margrave of Meissen, Princely Count of Henneberg, Lord of Blankenhayn, Neustadt and Tautenburg.