Landtag of Prussia

After World War I and the German Revolution of 1918–19 the Landtag diet continued as the parliament of the Free State of Prussia between 1921 and 1934, when it was abolished by the Nazi regime.

In the course of the 1848 Revolution, King Frederick William IV of Prussia and his Minister President Gottfried Ludolf Camphausen had agreed to call for the general election of a national assembly in all Prussian provinces.

It contained a catalog of fundamental rights that included freedom of religion, speech and the press, and provided for a bicameral parliament consisting of a First Chamber (Erste Kammer, called House of Lords from 1855), as well as a Second Chamber (Zweite Kammer, from 1855 House of Representatives) whose members were elected by universal manhood suffrage according to the three-class franchise system that weighted votes based on amount of taxes paid.

Under the regency of Prince William I and his liberal prime minister Prince Karl Anton von Hohenzollern from 1858 (the "New Era"), the House of Representatives led by the newly established German Progress Party gradually developed into a serious political actor, culminating in a constitutional conflict in 1861: William I, who had just acceded to the Prussian throne, and his war minister Albrecht von Roon requested approval for an increment of the military budget, which the deputies refused.

Bismarck acted on an alleged gap in the constitution (Lückentheorie) and openly sidestepped any power of the purse of the Prussian representatives, saying that "not by speeches and votes of the majority are the great questions of the time decided (...) but by iron and blood."

In September 1866 the Minister President, at a peak of his power after the Battle of Königgrätz, reached the passage of the Indemnity Act (Indemnitätsgesetz) subsequently legalising his budget management.

After the failed Kapp Putsch of 1920, the assembly confirmed the first cabinet of Minister-president Otto Braun and finally adopted the new Prussian constitution on 30 November.