The Duchy of Brunswick-Lüneburg (), or more properly the Duchy of Brunswick and Lüneburg, was a historical duchy that existed from the late Middle Ages to the Late Modern era within the Holy Roman Empire, until the year of its dissolution. The duchy was located in what is now northwestern Germany. Its name came from the two largest cities in the territory: Brunswick and Lüneburg. The dukedom emerged in 1235 from the allodial lands of the House of Welf in Saxony and was granted as an imperial fief to Otto the Child, a grandson of Henry the Lion. The duchy was divided several times during the High Middle Ages amongst various lines of the House of Welf, but each ruler was styled "Duke of Brunswick-Lüneburg" in addition to his own particular title. By 1692, the territories had consolidated to two: the Electorate of Brunswick-Lüneburg (commonly known as Electorate of Hanover) and the Principality of Brunswick-Wolfenbüttel. In 1714, the Hanoverian branch of the family succeeded to the throne of Great Britain, which they ruled in personal union with Hanover until 1837. For this reason, many cities and provinces in former British colonies are named after Brunswick or Lüneburg. The Hanoverians never ruled Brunswick while they held the British throne, as the city was part of neighbouring Brunswick-Wolfenbüttel. After the Congress of Vienna in 1814/15, the Brunswick-Lüneburg territories became the Kingdom of Hanover and the Duchy of Brunswick. History When the imperial ban was placed on Henry the Lion in 1180, he lost his titles as Duke of Saxony and Duke of Bavaria. He went into exile for several years, but was then allowed to stay on the (allodial) estates inherited from his mother's side until the end of his life. At the Imperial Diet of 1235 in Mainz, as part of the reconciliation between the Hohenstaufen and Welf families, Henry's grandson, Otto the Child, transferred his estates to Emperor Frederick II and was enfeoffed in return with the newly created Duchy of Brunswick-Lüneburg, which was formed from the estates transferred to the Emperor as well as other large areas of the imperial fisc. After his death in 1252, he was succeeded by his sons, Albert the Tall and John, who ruled the dukedom jointly. In 1269 the duchy was divided, Albert receiving the southern part of the state around Brunswick and John the northern territories in the area of Lüneburg. The