Holy Roman Empire

The Holy Roman Empire, also known as the Holy Roman Empire of the German Nation after 1512, was a polity comprising and controlling much of Central Europe and Western Europe, headed by the Holy Roman Emperor and characterized by a decentralized political structure. It developed in the Early Middle Ages (beginning in either 800 or 962), and lasted for a millennium until its dissolution in 1806 during the Napoleonic Wars. Initially, it consisted of three parts—Germany, Italy, and (from 1032) Burgundy—held together by the emperor's overlordship. By the 15th century, imperial governance had become concentrated in and upon the Kingdom of Germany, as the empire's effective control over Italy and Burgundy had largely disappeared.

On 25 December 800, Pope Leo III crowned Charlemagne (the Frankish king) as Roman Emperor, reviving the title more than three centuries after the fall of the Western Roman Empire in 476. The title had again lapsed by 924 but was revived again in 962 with the crowning of Otto of Saxony as emperor by Pope John XII. Otto the Great (as he became known), was King of the Germans but as emperor he became Charlemagne's successor, ruling in lands that had been first brought together as the Carolingian Empire. From 962 until the 13th century, the empire was one of the most powerful monarchies in Europe. It depended on continuing cooperation between emperors and still relatively powerful and independent vassals. The empire reached its apex in terms of territorial expansion and power in the mid-13th century, under the House of Hohenstaufen, but this was an overextension and led to a partial collapse.