Final answer:
The country known as Germany originated as Eastern Francia in the Carolingian Empire, with Otto I as its first Holy Roman Emperor. It was not fully unified until 1871 and became the Federal Republic of Germany in 1949. Germany reunified in 1990.
Step-by-step explanation:
The country established as Eastern Francia by the Carolingian Empire, with Otto I as its first Holy Roman Emperor, is Germany. After Charlemagne's death in 814, the lack of effective bureaucracy and cohesive law led to the fragmentation of the Carolingian Empire. The kingdom left to Louis the Pious's son became East Francia, which would later grow into the territory we now know as Germany.
Otto I, from a line not directly descended from the Carolingians, was crowned in 962, starting the Holy Roman Empire in earnest, which continued beyond Charlemagne's lineage. Germany was not politically united until 1871, following the failed Frankfurt Assembly and the successful unification efforts by Otto von Bismarck. The Federal Republic of Germany was established in 1949, and the country was reunified in 1990 after the fall of the Berlin Wall and the end of the Cold War.