Duchy of Brunswick-Lüneburg
The territory of Wolfenbüttel was recognized as a sovereign state by the Congress of Vienna in 1815. It had been a portion of the medieval Duchy of Brunswick-Lüneburg. From 1705 onward, all other portions of Brunswick-Lüneburg except Wolfenbüttel had been held by the Prince of Calenberg and Celle, i.e. the Elector of Hanover, but the Wolfenbüttel line retained its independence from Hanover.