In 1917, the British dukedom of Ernest Augustus's father, and his own title as a Prince of the United Kingdom of Great Britain and Ireland, were removed by the
Titles Deprivation Act 1917, which took effect in 1919, as a result of the Duke's service in the German army during the war. On 8 November 1918, Ernest Augustus was forced to abdicate his throne, as were all the other German kings, grand dukes, dukes, and princes during the
German Revolution of 1918–1919. Thus, when his father died in 1923, Ernest Augustus did not succeed to his father's title of Duke of Cumberland. For the next thirty years, Ernest Augustus remained as head of the House of Hanover, living in retirement on his various estates, mainly
Blankenburg Castle in Germany and
Cumberland Castle in Gmunden, Austria. He also owned
Marienburg Castle near Hanover, although rarely ever living there until 1945. Schloss Blankenburg (Harz) 003.jpg|
Blankenburg Castle near Brunswick Schloß Cumberland.jpg|Cumberland Castle,
Gmunden, Austria Panoramaaufnahme Schloss Marienburg cropped.jpg|
Marienburg Castle near Hanover While Ernest Augustus never officially joined the
Nazi Party, he donated funds and was close to several leaders. As a former British prince, Ernest Augustus, as well as Victoria Louise, desired a
rapprochement between the United Kingdom and Germany. Ostensibly desiring to pursue an alliance with the UK, in the mid-1930s,
Adolf Hitler took advantage of their sentiment by asking the couple to arrange a match between their daughter Princess Frederica and the
Prince of Wales. The Duke and Duchess of Brunswick refused, believing that the age difference was too great. After his abdication in 1936, Edward VIII and his wife visited "the Cumberlands" at Cumberland Castle in Gmunden, Austria. In 1938 Princess Frederica married Prince
Paul of Greece, brother and heir-presumptive of King
George II of Greece. By the time the Second World War ended in Europe in April 1945, he and his family were staying at Blankenburg. A few days before Blankenburg was handed over to the
Red Army by British and U.S. forces in late 1945, to become part of
East Germany, the family was able to move to
Marienburg Castle, at the time located in the
British Occupation Zone, with all their furniture, transported by British Army trucks, on the order of . in Hanover Ernest Augustus lived to see his daughter Frederica become a queen consort in 1947 when her husband Paul became King of the Hellenes. Ernest Augustus died at Marienburg Castle in 1953. He was interred, later to be joined by the remains of his wife, in front of the Royal Mausoleum in the Berggarten at
Herrenhausen Gardens in Hanover, which is the burial chapel of King Ernest Augustus of Hanover and his wife. ==Issue==