The Reichsrat was one of the two legislative bodies in Germany under the Weimar constitution, the other one being the Reichstag. After the end of German monarchy and the founding of the Weimar Republic in 1919, the Reichsrat replaced the Bundesrat as the representation of the various German states.
The Bundesrat had been the central body of the German federal state, which had been founded in 1867 as the North German Confederation and in 1871 became the German Empire. As this federal state comprised the various German kingdoms, principalities and free cities under the leadership of the King of Prussia, the Bundesrat comprised the delegates of the various states. Prussia sent almost half the representatives, being the largest state by far and so could block almost any decision. Also, the meetings of the Bundesrat were headed by the German chancellor appointed by the Kaiser, who usually was identical to the Prussian prime minister. The Bundesrat was a very powerful institution, as its consent was needed for any legislation. Also before the chancellor's secretaries gained prominence in the 1890s, the Bundesrat together with the chancellor effectively formed the federal government.
The Weimar constitution curbed the rights of the various states and the powers of their representation. The Reichsrat could use only a suspensive veto against the Reichstag's bills and had no influence on federal government. In contrast to the Bundesrat, it comprised not only representatives from the state governments, since half of the Prussian delegation was appointed by this state's various provincial parliaments. After Hitler came to power in 1933, the policy of Gleichschaltung first deprived the Reichsrat of its powers and later formally abolished it altogether, turning Germany into a centralized state.
After World War II, when the Federal Republic of Germany was founded the state's representation again was called Bundesrat and again became more powerful than the Reichsrat though not as powerful as the Bundesrat of the German Empire.