Prince Ernest Augustus of Hanover (born 1914)

In addition to being a German, he also held British nationality, after successfully claiming it under the Sophia Naturalization Act 1705 in the case of Attorney-General v. Prince Ernest Augustus of Hanover.

Nonetheless, a problem arose as foreign royal titles cannot be entered into a British passport.

He kept however the Princely House, a small palace built in 1720 by George I of Great Britain for his daughter Anna Louise.

Ernst August, Hereditary Prince of Brunswick, Prince of Hanover (Ernst August Prinz von Hannover; 18 March 1914 – 9 December 1987) was head of the House of Hanover from 1953 until his death in 1987.

He was also, shortly after birth in 1914, made a British prince by King George V of the United Kingdom, and was heir to the titles Duke of Cumberland and Teviotdale and Earl of Armagh.

The christening of Ernst August in the summer of 1914 was the last great gathering of European monarchs before the start of World War I.

He had an illustrious list of godparents: George V of the United Kingdom, Franz Joseph I of Austria, Nicholas II of Russia, Ludwig III of Bavaria, Frederick Francis IV, Grand Duke of Mecklenburg-Schwerin, Prince Adalbert of Prussia, Prince Oskar of Prussia, Prince Maximilian of Baden, the 1st Royal Bavarian Heavy Cavalry Regiment, and all four of his grandparents: the German Emperor and Empress and the Duke and Duchess of Cumberland.

Ernest Augustus was himself an heir to the British titles of Prince of Great Britain and Ireland, recognised ad personam for Ernst August's father as well as for him and his siblings by King George V of the United Kingdom on 17 June 1914, Duke of Cumberland and Teviotdale, Earl of Armagh, which however were all suspended under the Titles Deprivation Act 1917.

Therefore, the titles Prince of Hanover, Duke of Brunswick and Lüneburg could not be mentioned there, nor could the British titles due to the Titles Deprivation Act of 1917.

The name which was finally entered into his British documents, was thus Ernest Augustus Guelph, with the addition of His Royal Highness.

Guelph is thus also the British last name of his siblings and children, all styled Royal Highnesses in the United Kingdom.

From his birth until the German Revolution of 1918–1919 he was the heir apparent to the Duchy of Brunswick, a state of the German Empire.

He was born at Braunschweig, Germany, the eldest son of Ernest Augustus, Duke of Brunswick and Princess Viktoria Luise of Prussia, the only daughter of Emperor Wilhelm II, Ernest Augustus's third cousin in descent from George III of the United Kingdom.

Ernst August's parents were, therefore, third cousins, once removed.

From his birth, he was the Hereditary Prince of Brunswick.

He ceased being heir to the duchy of Brunswick at the age of four, when his father abdicated in 1918.

His German titles were abolished in 1919 by the Weimar Republic, while his British titles were suspended under the Titles Deprivation Act 1917.

Nonetheless he carried both as titles of pretence during his lifetime.

He had joined the SS in 1933 and remained a member for one year.

In 1938 his sister, Princess Frederica had married the later King Paul I of the Hellenes and in 1946 his younger brother Prince George William married Princess Sophie of Greece and Denmark, thus becoming the brother-in-law of Prince Philip, Duke of Edinburgh and Queen Elizabeth II of the United Kingdom.

During the Second World War, specifically in 1941, his cousin Prince Hubertus of Prussia married the noted society beauty and aristocrat Baroness Maria Anna von Humboldt-Dachroeden (1916–2003).

He was seriously injured near Kharkiv in spring 1943.

The couple, however, divorced in 1943, after her affair with Ernest Augustus resulted in the birth of a son.

Ernest Augustus however did not marry Maria Anna because his parents would not have approved, since she was considered of inadequate birth and was also a divorcée, and the marriage would have made his younger brother Prince George William heir to the headship of the House of Hanover.

The child, christened Christian Ernst August Hubertus, Freiherr von Humboldt-Dachroeden, was born in 1943 and currently is a bank consultant.

After the 20 July plot in 1944, he was imprisoned for a few weeks by the Gestapo in Berlin.

His official "denazification" certificate from 1949 vetting his Third Reich associations classified him as "a nominal Nazi supporter", without being a Nazi party member, and according to a Foreign Office record.

On 5 September 1951, Ernest Augustus married Princess Ortrud of Schleswig-Holstein-Sonderburg-Glücksburg (1925–1980).

The wedding was attended by many important royal figures, including his sister Queen Frederica and her husband King Paul of Greece, and the heads of the houses of Saxony, Hesse, Mecklenburg, Oldenburg, and Baden.

The wedding was followed with a reception in the Gallery Building at Herrenhausen Gardens, the only part of the House of Hanover's former summer palace still intact, as the palace itself had been burned down during World War II.

His children by his first wife are:

After his father's death in 1953, he became head of the House of Hanover.

During World War II, he fought at the Russian Front as Oberleutnant in the staff of Generaloberst Erich Hoepner.

Ernest Augustus converted Marienburg Castle into a museum in 1954, after having moved to nearby Calenberg Demesne, which caused a row with his mother, who was forced to move out.

In 1961 he sold his remaining properties at Herrenhausen Gardens, including the site of Herrenhausen Palace which had been destroyed by a British bombing raid in 1943.

He also sold the family's exile seat, Cumberland Castle at Gmunden, Austria, to the state of Upper Austria in 1979, but his family foundation based in Liechtenstein kept vast forests, a game park, a hunting lodge, The Queen's Villa and other property at Gmunden.

The family property is now managed by his grandson Ernst August.

Princess Ortrud died in 1980.

Ernest Augustus married again in 1981, Countess Monika zu Solms-Laubach (1929–2015), daughter of Georg, 9th Count of Solms-Laubach (1899-1969) and his wife, Princess Johanna of Solms-Hohensolms-Lich (1905-1982).

He died at Schulenburg, Pattensen, Lower Saxony, Germany, aged 73, and was buried next to his first wife on a round bastion of Marienburg Castle (Hanover).