It was disestablished after the end of World War I, its territory incorporated into the Weimar Republic as the Free State of Brunswick.

It is widely understood and confirmed that from the year 1546 forward there became two dynastic lines of the house of Este-Guelph Brunswick: "the senior", from Brunswick-Wolfenbuettel, and one called "the younger branch" from Calenburg-Hanover.

[clarification needed] The princes of Wolfenbüttel maintained their supremacy over the subject vassal state of Lüneburg, but recognized its semi-sovereignty.

His absolutist governing style had alienated the nobility and bourgeoisie, while the lower classes were disaffected by the bad economic situation.

During the night of 7–8 September 1830, the ducal palace in Braunschweig was stormed by an angry mob, set on fire and destroyed completely.

[3] When Charles' brother William VIII arrived in Brunswick on 10 September, he was received joyfully by the people.

As a result, Prussia was unwilling to let George V of Hanover or his son, Ernest Augustus, succeed to Brunswick.

Berlin would only agree to the Hanoverians becoming dukes of Brunswick under severe conditions, including swearing allegiance to the German constitution and renouncing all claim to Hanover.

If Ernest Augustus–who had been created the Duke of Cumberland in the British peerage–were unable to succeed, the council would also be empowered to appoint a regent.

However, since he still claimed to be the rightful King of Hanover, the Federal Council ruled that he would violate the peace of the German Empire if he succeeded to Brunswick.

The Duke of Cumberland's eldest son having died in 1912, the elderly duke renounced Brunswick in favor of his youngest son, Ernest Augustus, who married Emperor Wilhelm II's daughter, swore allegiance to the German Empire and renounced all claims to Hanover.

The biggest and most populous of those was the area surrounding the cities of Braunschweig, Wolfenbüttel and Helmstedt as well as the Elm, which extended from the river Aller in the north to the Harz mountains in the south.

The western part with the town of Holzminden extended from the river Weser in the east to the Harz Foreland in the west.

The Duchy's smaller exclaves were Thedinghausen near Bremen, Harzburg, Calvörde, Bodenburg and Östrum, Ostharingen near Goslar, Ölsburg near Peine and a small woodland near the Fallstein.

The major rivers that ran through Brunswick were the Weser, Aller, Leine, Oker, Bode and Innerste.

[12][13] The Duchy of Brunswick Football Association (German: Fußballbund für das Herzogtum Braunschweig) was founded in May 1904.

Later accounts by medieval writers that the two golden lions of Brunswick were granted to Henry by the English king, his father-in-law, are deemed fictional by modern historians.

The lesser coat of arms of the Duchy of Brunswick showed a crowned shield with the white horse on a red background.

[20] The greater coat of arms of the Duchy of Brunswick, as adopted in 1834, shows a shield with a ducal crown on top and surrounded by the insignia of the Order of Henry the Lion.

Displayed on the shield are, from left to right, the blue lion of Lüneburg, the two lions of Brunswick, and the arms of the Counts of Eberstein, Homburg, Diepholz (upper half), Lauterberg, Hoya and Bruchhausen, Diepholz (lower half), Honstein, Regenstein, Klettenberg and Blankenburg.

The Latin inscriptions read IMMOTA FIDES ("unswerving faithfulness") and NEC ASPERA TERRENT ("they are not afraid of difficulties").

The standard of the dukes of Brunswick given by Siebmachers Wappenbuch, Nuremberg 1878, shows the white horse on a red cloth - this, however, is today assumed to have been in error.

[22] The state flag introduced in 1912 was blue over yellow, with a crowned shield with the white horse on a red background in the center.