Hanover (German: Hannover) is a territory that was at various times a principality within the Holy Roman Empire, an Electorate within the same, an independent Kingdom, and a subordinate Province within the Kingdom of Prussia. The territory was named after its capital, the city of Hanover, which was the principal town of the region from 1636. In contemporary usage, the name is only used for the city; most of the historical territory of Hanover forms the greater part of the German Land of Lower Saxony but excludes certain areas.
Hanover was formed by the union of several dynastic divisions of the Duchy of Brunswick-Lüneburg, with the sole exception of Brunswick-Wolfenbüttel. From 1714 to 1837, it was joined in a personal union with the United Kingdom, which terminated upon the accession in Britain of Queen Victoria, as in Hanover, a woman could not rule if there was a male descendent. Until 1803, when it was occupied by French and Prussian troops, Hanover was a constituent state of the Holy Roman Empire; when it regained independence in 1814, Hanover was raised to a kingdom, which lasted until 1866.
The title "Duke of Brunswick and Lüneburg" (German: Herzog zu Braunschweig und Lüneburg) was held, from 1235, by various members of the Welf family who ruled several small territories in northwest Germany. These holdings did not have all of the formal characteristics of a state, being neither compact nor indivisible. When several sons of a Duke competed for power, the lands were often divided between them; when a branch of the family lost power or became extinct, the lands were reallocated among surviving members of the family; different dukes might also exchange territories. The territories were named after notable towns where the dukes had (or had had at one time) their residences, e.g. Calenberg, Göttingen, Grubenhagen, Lüneburg, Wolfenbüttel. The unifying element of all these territories was that they were ruled by male-line descendants of Duke Otto I, Duke of Brunswick-Lüneburg, nephew of the Holy Roman Emperor Otto IV.