In 1949 with the continuation and aggravation of the Cold War (witness the Berlin Airlift of 1948–49), the two German states that were originated in the Western Allied and the Soviet Zones became known internationally as West Germany and East Germany. Commonly known in English as East Germany , the former Soviet Occupation Zone , eventually became the German Democratic Republic or GDR . In 1990 West Germany and East Germany jointly signed the Treaty on the Final Settlement With Respect to Germany ; by which transitional status of Germany following World War II was definitively ended, the Four Allied powers relinquished their joint residual sovereign authority for Germany as a whole, the two parts of Germany confirmed their post-war external boundaries as final and irreversible (including the 1945 transfer of former German lands east of the Oder-Neisse line ), and the Allied Powers confirmed their consent to German Reunification. From 3 October 1990, after the reformation of the GDR's Länder , the East German states joined the Federal Republic .
In 800, the Frankish king Charlemagne was crowned emperor and founded the Carolingian Empire , which was later divided in 843 among his heirs.  Following the break up of the Frankish Realm, for 900 years, the history of Germany was intertwined with the history of the Holy Roman Empire ,  which subsequently emerged from the eastern portion of Charlemagne's original empire. The territory initially known as East Francia stretched from the Rhine in the west to the Elbe River in the east and from the North Sea to the Alps .  The Ottonian rulers (919–1024) consolidated several major duchies and the German king Otto I was crowned Holy Roman Emperor of these regions in 962. In 996 Gregory V became the first German Pope, appointed by his cousin Otto III , whom he shortly after crowned Holy Roman Emperor. The Holy Roman Empire absorbed northern Italy and Burgundy under the reign of the Salian emperors (1024–1125), although the emperors lost power through the Investiture Controversy .