The German word Landtag is composed of the words Land (state, country or territory) and Tag (day). The German word Tagung (meeting) is derived from the German word Tag, as such meetings were held at daylight and sometimes spanned several days.
Historic Landtag assemblies
States of the Holy Roman Empire
In feudal society, the formal class system was reflected in the composition of the Imperial States' representative assemblies (Landstände), regardless of their name well described as estates of the realm: it was not intended as an elected reflection of public opinion, but a fixed expression of established power as recognized in formal privileges, including the right to be seated in person (granted to many nobles (knightage) and prelates, as well as certain cities) or to be represented as elector in a college that is entitled to one or more seats. Therefore, the representatives primarily defended class interests, and decisions were based on a class-based electoral system.
In some of the Imperial States that were known as Land, the name of such estates assembly was Landtag, analogous to the Reichstag (Imperial Diet), which mainly comprised most of the Princes of the Holy Roman Empire plus Reichsgrafen, Imperial prelates and Free imperial cities. The precise composition obviously varied greatly, and could change over time, as the result of privileges granted or lost, entities split or merged, border changes et cetera.
As Austria and Prussia escaped the French 'exporting the revolution', and Napoleon was happy to maintain satellite monarchies in most German territories under his control (members of the Confederation of the Rhine), the more democratic principles of the Enlightenment would have less effect in the German-speaking lands, or only much later.
In 1815 the German Confederation ("Deutscher Bund") was founded as successor to the Holy Roman Empire. § 13 of the "Bundesakte" (the constitution of the German Confederation) forced the German states to pass constitutions and implement parliaments called Landstände or Landtage.
In 1871 the German Empire was founded. All 25 states of the German Empire and Alsace-Lorraine (the "Reichsland Elsaß-Lothringen") (from 1911) had Landtage as legislative authorities. The most important one was the Prussian Landtag.
States of the Weimar Republic
In the Weimar Republic (1919 – 1933) all German states had Landtage that were democratically elected by universal suffrage, and to which the state governments were responsible. After the Nazi seizure of power, they embarked on the process of Gleichschaltung (coordination). On 31 March 1933, the Provisional Law on the Coordination of the States with the Reich was enacted, which dissolved all the sitting Landtage and reconstituted them on the basis of the recent Reichstag election results, which had given the Nazi Party and its coalition partner the DNVP a working majority. This was followed by the "Law on the Reconstruction of the Reich" of 30 January 1934 that formally abolished all the Landtage and transferred the sovereignty of the states to the central government. Although the states themselves continued in existence, the federalism of the Republic was effectively supplanted by a unitary state.
In 1952, the Länder were dissolved and replaced by Bezirke (districts). The Landtage were accordingly abolished and their functions transferred to the Bezirke governments. The Länder were eventually restored after the Peaceful Revolution, but their Landtage did not convene until after the reunification of Germany.
Finland
The Diet of Finland, which was created when the country was ceded from Sweden to Russia in 1809, was called lantdag in Swedish until 1906 when it was replaced by the unicameral Parliament of Finland. Parliament continued using the name lantdag in Swedish until 1919, when Finland adopted its first constitution following the declaration of independence in 1917. Since then, the official term in Swedish has been riksdag, equivalent of the German Reichstag. The Finnish name is eduskunta.
Landtag of Bavaria (until 1999, the large federal state of Bavaria was the only state with a bicameral legislature, with a lower house called the Landtag, and an upper house called the Senate)
The national bicameral Parliament comprises the directly elected Bundestag and the Bundesrat which represents the state governments in Federal matters which affect the Länder.
According to the Constitution of Austria, the Landtage are the unicameral legislatures of the nine states of Austria (Bundesländer), dealing with all matters not explicitly allotted to federal level:
As the Austrian capital Vienna (like Berlin) is both a city-state and a municipality, the Gemeinderat (municipal assembly) of Vienna also serves as the state Landtag. However, the city constitution states that municipal and state affairs are kept separate, and the two bodies hold separate meetings even though their memberships are identical.
The representatives are elected in general, free, secret and direct ballots according to the principle of proportional representation. The largest of the parliamentary groups (called Klubs in Austria) usually nominates the Landeshauptmann governor. The modern Landtage are the democratic successors of the estates assemblies in the corresponding crown lands of the Austrian Empire. Exceptions are the city of Vienna, which belonged to the Lower Austria Kronland until 1920, and Burgenland, ceded to Austria by the Kingdom of Hungary in 1921.
Austria's national bicameral parliament consists of the directly elected National Council and the Federal Council, which represents the Landtage parliaments at the federal level. The two chambers meet in the Federal Assembly, held for the ceremonial swearing-in of the Austrian president.
