State of Thuringia (1920–1952) in the context of Thuringian states

Saxe-Weimar-Eisenach (German: Sachsen-Weimar-Eisenach) was a German state, 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 Congress of Vienna. 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.

The People's State of Reuss (German: Volksstaat Reuß) was a small, short-lived (1918–1920) central German state during the early years of the Weimar Republic. It was formed following the dissolution of the principalities of Reuss-Gera and Reuss-Greiz during the German revolution of 1918–1919. After Prince Heinrich XXVII abdicated for both principalities, they joined to form the People's State of Reuss. It became part of the new state of Thuringia when it was created on 1 May 1920.

Saxe-Coburg and Gotha (German: Sachsen-Coburg und Gotha), or Saxe-Coburg-Gotha (German: Sachsen-Coburg-Gotha [ˈzaksn̩ ˈkoːbʊʁk ˈɡoːta]), was an Ernestine duchy in Thuringia ruled by a branch of the House of Wettin, consisting of territories in the present-day states of Thuringia and Bavaria in Germany. It lasted from 1826 to 1918. In November 1918, Charles Edward, Duke of Saxe-Coburg and Gotha, was forced to abdicate. In 1920, the northern part of the duchy (since 1918 the Free State of Gotha; culturally and linguistically Thuringian) was merged with six other Thuringian free states to form the Free State of Thuringia: Saxe-Weimar-Eisenach (until 1918 a grand duchy), Saxe-Altenburg and Saxe-Meiningen (until 1918 duchies), Schwarzburg-Rudolstadt and Schwarzburg-Sondershausen (until 1918 principalities), as well as the People's State of Reuss (until 1918 the principalities of Reuss-Gera and Reuss-Greiz). The southern part of the duchy (since 1918 the Free State of Coburg; culturally and linguistically Franconian), as southernmost of the Thuringian states, was the only one which, after a referendum, became part of the Free State of Bavaria.

The name Saxe-Coburg-Gotha also refers to the family of the ruling House of Saxe-Coburg and Gotha, which played many varied roles in the dynastic and political history of Europe in the 19th and 20th centuries. In the early part of the 20th century, before the First World War, it was the family of the sovereigns of the United Kingdom, Belgium, Portugal, Bulgaria, and Saxe-Coburg-Gotha. In 1910, the Portuguese king was deposed, and the same thing occurred in Saxe-Coburg-Gotha in 1918 and in Bulgaria in 1946 (although effective control had already ceased two years prior due to a coup). As of 2025, a branch of the family still reigns in Belgium, and while the British line still technically exists up to the present day, it now uses the name Windsor due to a proclamation issued by King George V in 1917. The former Tsar of Bulgaria, Simeon II (reigned 1943–46), kept his surname while serving as the Prime Minister of Bulgaria from 2001 to 2005.

The states of the Weimar Republic were the first-level administrative divisions and constituent states of the Weimar Republic. The states were established in 1918–1920 following the German Empire's defeat in World War I and the territorial losses that came with it. They were based on the 22 states and three city-states of the German Empire. During the revolution of 1918–1919, the states abolished their local monarchies and adopted republican constitutions.

Several attempts were made to reorganize the states under the Weimar Republic, particularly because of Prussia's disproportionately large size and influence, but the attempts were unsuccessful. The one significant change was the formation of Thuringia from a number of smaller states.

The Free State of Saxe-Weimar-Eisenach (German: Freistaat Sachsen-Weimar-Eisenach) was a small, short-lived (1918–1920) central German state during the early years of the Weimar Republic. It was formed following the dissolution of the Grand Duchy of Saxe-Weimar Eisenach during the German revolution of 1918–1919. After Grand Duke William Ernest abdicated, Saxe-Weimar Eisenach transitioned peacefully into a republic. It became part of Thuringia when it was created on 1 May 1920.

The Free State of Saxe-Gotha (German: Freistaat Sachsen-Gotha) was a small, short-lived (1918–1920) central German state during the early years of the Weimar Republic. It was formed following the dissolution of the Duchy of Saxe-Coburg and Gotha during the German revolution of 1918–1919. Saxe-Coburg split away and formed a separate state due in part to the more radical nature of the revolution in Saxe-Gotha. The federal government saw the strength of Saxe-Gotha's workers' movement as a potential threat and twice sent troops against them.

The Free State of Saxe-Gotha was formally established as a parliamentary republic shortly before it merged with six other small states to form Thuringia on 1 May 1920. Coburg became part of Bavaria two months later.

The Free State of Coburg (German: Freistaat Coburg) was a small, short-lived (1918–1920) central German state during the early years of the Weimar Republic. It was formed following the dissolution of the Duchy of Saxe-Coburg and Gotha during the German revolution of 1918–1919. Duke Charles Edward abdicated, and Coburg separated from Saxe-Gotha due in large part to political differences with its more radical neighbor. After Coburg's peaceful transition to a republican government, the majority of the population rejected a union with Thuringia, and Coburg merged instead with Bavaria on 1 July 1920.