Henry lost the election, as the other princes feared his power and temperament, and was dispossessed of his duchies by Conrad III.

The next duke of the Welf dynasty Henry the Lion (1129/1131–1195) recovered his father's two duchies, Saxony in 1142, Bavaria in 1156 and thus ruled vast parts of Germany.

His first cousin, Frederick I, Holy Roman Emperor of the Hohenstaufen dynasty, tried to get along with him, but when Henry refused to assist him once more in an Italian war campaign, conflict became inevitable.

Dispossessed of his duchies after the Battle of Legnano in 1176 by Emperor Frederick I and the other princes of the German Empire eager to claim parts of his vast territories, he was exiled to the court of his father-in-law Henry II in Normandy in 1180.

Henry made his peace with the Hohenstaufen Emperor in 1185 and returned to his much diminished lands around Brunswick without recovering his two duchies.

Henry the Lion's grandson Otto the Child became duke of a part of Saxony in 1235, the new Duchy of Brunswick-Lüneburg, and died there in 1252.

All members of the House of Welf, male or female, bore the title Duke/Duchess of Brunswick-Lüneburg in addition to the style of the subordinate principality.

Religion-driven politics placed Ernest Augustus's wife Sophia of the Palatinate in the line of succession to the British crown by the Act of Settlement 1701, written to ensure a Protestant succession to the thrones of Scotland and England at a time when anti-Catholic sentiment ran high in much of Northern Europe and Great Britain.

Sophia died shortly before her first cousin once removed, Anne, Queen of Great Britain, the last sovereign of the House of Stuart.

Sophia's son George I succeeded Queen Anne and formed a personal union from 1714 between the British crown and the Electorate of Hanover, which lasted until well after the end of the Napoleonic Wars more than a century later, through the dissolution of the Holy Roman Empire and the rise of a new successor kingdom.

The senior line of the dynasty had ruled the much smaller principality of Brunswick-Wolfenbüttel, created the sovereign Duchy of Brunswick in 1814.

Although the Duchy should have been inherited by the Duke of Cumberland, son of the last king of Hanover, Prussian suspicions of his loyalty led the duchy's throne to remain vacant until 1913, when the Duke of Cumberland's son, Ernst August, married the daughter of Kaiser Wilhelm II and was allowed to inherit it.

The House's head is Queen Frederica's nephew Ernst August, the third and present husband of Princess Caroline of Monaco.

In 1129, after Henry the Proud's defeat against Lothair III, Holy Roman Emperor, his sister Sophia was given a seat at Regensburg.

However, 1373–1388 would be the only period in which a Brunswick-Luneburg land was not ruled by a Welf: In the wake of his death, Elector Wenceslas appointed Bernard, his brother-in-law, as co-regent involved him in the government.

But his younger brother Henry did not agree with this ruling, and after vain attempts to reach an agreement, the fight flared up again in the spring of 1388.

Lüneburg continued the preparations, formed an alliance with the Bishop of Minden and Count of Schaumburg and set up his own army.