German kingdom

The Kingdom of Germany or German Kingdom (Latin: Regnum Teutonicum, "Teutonic Kingdom"; German: Deutsches Reich) developed out of the eastern half of the former Carolingian Empire. Like Anglo-Saxon England and medieval France, it began as "a conglomerate, an assemblage of a number of once separate and independent... gentes [peoples] and regna [kingdoms]."East Francia (Ostfrankenreich) was formed by the Treaty of Verdun in 843, and was ruled by the Carolingian dynasty until 911, after which the kingship was elective. The initial electors were the rulers of the stem duchies, who generally chose one of their own. After 962, when Otto I was crowned emperor, the kingdom formed the bulk of the Holy Roman Empire, which also included Italy (after 951), Bohemia (after 1004) and Burgundy (after 1032).

The term rex teutonicorum ("king of the Germans") first came into use in the chancery of Pope Gregory VII during the Investiture Controversy (late 11th century), perhaps as a polemical tool against Emperor Henry IV. In the twelfth century, in order to stress the imperial and transnational character of their office, the emperors began to employ the title rex Romanorum (king of the Romans) on their election (by the prince-electors, seven German bishops and noblemen). Distinct titulature for Germany, Italy and Burgundy, which traditionally had their own courts, laws, and chanceries, gradually dropped from use. After the Imperial Reform and Reformation settlement, the German part of the Holy Roman Empire was divided into Reichskreise (imperial circles), which effectively defined Germany against imperial Italy and the Bohemian Kingdom. There are nevertheless relatively few references to a German realm and an instability in the term's use.

...
Wikipedia