In 1952, following a referendum, Baden, Württemberg-Baden, and Württemberg-Hohenzollern merged into Baden-Württemberg. In 1957, the Saar Protectorate rejoined the Federal Republic as the Saarland. <answer>German reunification</answer> in 1990, in which the German Democratic Republic (East Germany) ascended into the Federal Republic, resulted in the addition of the re-established eastern states of Brandenburg, Mecklenburg-West Pomerania (in German Mecklenburg-Vorpommern), Saxony (Sachsen), Saxony-Anhalt (Sachsen-Anhalt), and Thuringia (Thüringen), as well as the reunification of West and East Berlin into Berlin and its establishment as a full and equal state. A regional referendum in 1996 to merge Berlin with surrounding Brandenburg as "Berlin-Brandenburg" failed to reach the necessary majority vote in Brandenburg, while a majority of Berliners voted in favour of the merger.
What was it called when East Germany joined the republic?
German reunification