The Socialist Unity Party (SED) was a political party in East Germany, officially known as the German Democratic Republic (GDR). Founded in 1946, it emerged from a merger of the Communist Party of Germany and the Social Democratic Party. The SED played a central role in the GDR's government and was the ruling party until the reunification of Germany in 1990. The party promoted socialist policies and aimed to create a classless society. It was closely aligned with the Soviet Union and followed Marxist-Leninist principles. The SED faced significant opposition during the Peaceful Revolution of 1989, which ultimately led to its dissolution.