stylistic:tone
The Holy Roman Empire, also known as the Holy Roman Empire of the German Nation after 1512, was a polity in Central and Western Europe, usually headed by the Holy Roman Emperor. It developed in the Early Middle Ages and lasted for almost a thousand years until its dissolution in 1806 during the Napoleonic Wars.

On 25 December 800, Pope Leo III crowned Frankish king Charlemagne as Roman emperor, reviving the title in Western Europe more than three centuries after the fall of the ancient Western Roman Empire in 476. The title lapsed in 924, but was revived in 962 when Otto I was crowned emperor by Pope John XII, fashioning himself as Charlemagne's and the Carolingian Empire 's successor, and beginning a continuous existence of the empire for over eight centuries. From 962 until the 12th century, the empire was one of the most powerful monarchies in Europe. The functioning of government depended on the harmonious cooperation between emperor and vassals; this harmony was disturbed during the Salian period. The empire reached the apex of territorial expansion and power under the House of Hohenstaufen in the mid-13th century, but overextension of its power led to a partial collapse.

Scholars generally describe an evolution of the institutions and principles constituting the empire, and a gradual development of the imperial role. While the office of emperor had been reestablished, the exact term for his realm as the "Holy Roman Empire" was not used until the 13th century, although the emperor's theoretical legitimacy from the beginning rested on the concept of translatio imperii, that he held supreme power inherited from the ancient emperors of Rome. Nevertheless, in the Holy Roman Empire, the imperial office was traditionally elective by the mostly German prince-electors. In theory and diplomacy, the emperors were considered the first among equals of all Europe's Catholic monarchs.

A process of Imperial Reform in the late 15th and early 16th centuries transformed the empire, creating a set of institutions which endured until its final demise in the 19th century. According to historian Thomas Brady Jr., the empire after the Imperial Reform was a political body of remarkable longevity and stability, and "resembled in some respects the monarchical polities of Europe's western tier, and in others the loosely integrated, elective polities of East Central Europe." The new corporate German Nation, instead of simply obeying the emperor, negotiated with him. On 6 August 1806, Emperor Francis II abdicated and formally dissolved the empire following the creation – the month before, by French emperor Napoleon – of the Confederation of the Rhine, a confederation of German client states loyal not to the Holy Roman emperor but to France.