German reunification means the end of the German partition and the unification of the two German states, the German Democratic Republic (GDR) and the Federal Republic of Germany (FRG), that were created after the Second World War. After the collapse of the East German regime and the democratisation of the GDR both states decided to reunite. To allow for the legal reunification, the four allies, the United States, France, the United Kingdom and the Soviet Union together with the two German states negotiated the treaty on the Final Settlement with Respect to Germany, also called “Two Plus Four Agreement”. The agreement guaranteed the unified German state full sovereignty. Following article 23 in the federal German basic law, the GDR joined the FRG and merged into the Federal Republic on 3 October 1990. Berlin became the new capital of the unified German state.