The Kingdom of Hanover began its life in 1814, before then it had been the Electorate of Hanover. The Electorate had been in personal union with the Kingdom of Great Britain when the Elector of Hanover succeeded as King George I of Great Britain through the Act of Settlement 1701. His mother was Sophia, a granddaughter of King James VI and I. During the Napoleonic Wars the Electorate fell to the French and it was not only restored in 1814, but it was then elevated to a Kingdom.
Its first King was King George III of Great Britain, who was married to Charlotte of Mecklenburg-Strelitz, who was thus the First Queen of Hanover. Charlotte and George had 15 children together, of which 13 survived to adulthood. George III probably suffered from the blood disease porphyria, and from 1811 he was under the regency of his eldest son, also named George. Upon his father’s death in 1920, he became King George IV. George had married Caroline of Brunswick in 1795, but the marriage was unhappy and produced only a daughter named Charlotte, who predeceased him. In any case, Charlotte would not have been able to succeed him in Hanover, which still operated under semi-salic law and barred women from the throne while any male dynast lived.
Upon his death in 1830, he was succeeded by his younger brother, now King William IV. William had been living with his mistress Dorothea Jordan for twenty years, and they had ten children together, who were all considered illegitimate. When it became clear that the succession was in danger, William married Princess Adelaide of Saxe-Meiningen in 1818. They would go on to have five children, though tragically, none survived to adulthood. When William died in 1837, he was succeeded as King of the United Kingdom, as it was now known, by his niece Princess Victoria, the daughter of Prince Edward, Duke of Kent. As she could not succeed to the Hanoverian throne, due to the semi-salic law explained above, he was succeeded as King of Hanover by his brother Ernest Augustus, Duke of Cumberland and Teviotdale, who was the fifth son of King George III.
Ernest Augustus had married the twice-widowed Frederica of Mecklenburg-Strelitz and together they had three children together, of which only one son survived to adulthood. Upon Ernest Augustus’ death in 1851, he was succeeded by his only son, now King George V. George had married Marie of Saxe-Altenburg in 1843, and they had one son and two daughters together. The outcome of the Austro-Prussian War in 1866 led to the dissolution of the Kingdom of Hanover, and it was annexed by the Kingdom of Prussia. It became part of the German Empire in 1871 and is now part of the Federal Republic of Germany. Thus, Marie of Saxe-Altenburg became the last Queen of Hanover.
George refused to accept the dissolution of the Kingdom. Upon his death in 1878, his claim to Hanover was inherited by his only son, Prince Ernest Augustus, 3rd Duke of Cumberland and Teviotdale. The claim is currently being held by Prince Ernst August of Hanover (born 1954), the great-grandson of Prince Ernest August.