On 25 December 800, Charlemagne founded the Carolingian Empire, which was divided in 843. The medieval empire resulted from the eastern portion of this division and existed in varying forms from 962 until 1806. Its territory stretched from the Eider River in the north to the Mediterranean coast in the south. Often referred to as the Holy Roman Empire (or the Old Empire), it was officially called the Sacrum Romanum Imperium Nationis Germanicæ (Holy Roman Empire of the German Nation) starting in 1448, to adjust the title to its then reduced territory.
Under the reign of the Ottonian emperors (919–1024), the duchies of Lorraine, Saxony, Franconia, Swabia, Thuringia, and Bavaria were consolidated, and the German king was crowned Holy Roman Emperor of these regions in 962. Under the reign of the Salian emperors (1024–1125), the Holy Roman Empire absorbed northern Italy and Burgundy, although the emperors lost power through the Investiture Controversy. Under the Hohenstaufen emperors (1138–1254), the German princes increased their influence further south and east into territories inhabited by Slavs, preceding German settlement in these areas and further east (Ostsiedlung). Northern German towns grew prosperous as members of the Hanseatic League. Starting with the Great Famine in 1315, then the Black Death of 1348–50, the population of Germany plummeted.[16]
The edict of the Golden Bull in 1356 provided the basic constitution of the empire that lasted until its dissolution. It codified the election of the emperor by seven prince-electors who ruled some of the most powerful principalities and archbishoprics. Beginning in the 15th century, the emperors were elected nearly exclusively from the Habsburg dynasty of Austria.
The monk Martin Luther publicised his 95 Theses in 1517, challenging practices of the Roman Catholic Church, initiating the Protestant Reformation. A separate Lutheran church became the official religion in many German states after 1530. Religious conflict led to the Thirty Years' War (1618–1648), which devastated German lands.[17] The population of the German states was reduced by about 30%.[18] The Peace of Westphalia (1648) ended religious warfare among the German states, but the empire was de facto divided into numerous independent principalities. From 1740 onwards, the dualism between the Austrian Habsburg Monarchy and the Kingdom of Prussia dominated German history. In 1806, the Imperium was overrun and dissolved as a result of the Napoleonic Wars.