The Grand Duchy of Hesse and by Rhine was a grand duchy in western Germany that existed from 1806 to the end of the German Empire in 1918. The grand duchy originally formed on the basis of the Landgraviate of Hesse-Darmstadt in 1806 as the Grand Duchy of Hesse. After the end of the Napoleonic Wars in 1815, it changed its name in 1816 to distinguish itself from the Electorate of Hesse, which had formed from neighboring Hesse-Kassel. Colloquially, the grand duchy continued to be known by its former name of Hesse-Darmstadt. It joined the German Empire in 1871 and became a republic after the German defeat in World War I in 1918.
History
Hesse-Darmstadt was a member of Napoleon's Confederation of the Rhine during the Napoleonic Wars. Rapidly expanding during the mediatizations, Hesse-Darmstadt became an amalgamation of smaller German states, such as the Electorate of Cologne. The legal patchwork of the state culminated in a decree issued on 1 October 1806 by Louis I. The old territorial estates were abolished, which altered Hesse-Darmstadt "from a mosaic of patrimonial fragments into a centralized, absolute monarchy." The Duchy of Westphalia, which Hesse-Darmstadt had received in 1803, was ceded to the Kingdom of Prussia during the Congress of Vienna. However, Hesse-Darmstadt was compensated with some territory on the western bank of the Rhine, including the important federal fortress at Mainz. The neighboring Landgraviate of Hesse-Kassel had backed Prussia against Napoleon and was absorbed into the Kingdom of Westphalia. At the Congress of Vienna, Hesse-Kassel was reestablished as the Electorate of Hesse. To distinguish the two Hessian states, the grand duchy changed its name to the Grand Duchy of Hesse and by Rhine in 1816. In 1867, the northern half of the Grand Duchy became a part of the North German Confederation, while the half of the Grand Duchy south of the Main remained outside. In 1871, it became a constituent state of the German Empire. The last Grand Duke, Ernst Ludwig, was forced from his throne at the end of World War I, and the state was renamed the People's State of Hesse. After World War II, the majority of the state combined with Frankfurt am Main, the Waldeck area and the former Prussian province of Hesse-Nassau to form the new state of Hesse. Excluded were the Montabaur district from Hessen-Nassau and that part of Hessen-Darmstadt on the left bank of the Rhine, which became part of the Rhineland-Palatinate state. Wimpfen—an exclave of Hessen-Darmstadt—became part of Baden-Württemberg, in the district of Sinsheim. After a plebiscite on 29 April 1951, Bad Wimpfen was transferred from Sinsheim district to Heilbronn District. This change to Heilbronn was carried out on 1 May 1952.
Transport
Because of the disjointed nature of the state, it did not develop its own state railway to begin with, but set up joint railway projects with its neighbouring states: These were the:
