Original: The Grand Duchy came to an end in the German Revolution of 1918 â "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.
Simplified: The Grand Duchy was abolished in 1918 with the other German monarchies, and the state joined others to form the new state of Thuringia in the Weimar Republic.