[3] His father had hoped that the young prince might marry his cousin, the future Queen Victoria, who was older by three days, thus keeping the British and Hanoverian thrones united.

Since he was totally blind, there were doubts as to whether the Crown Prince was qualified to succeed as king of Hanover, but his father decided that he should do so.

The Crown Prince succeeded his father as the King of Hanover and Duke of Brunswick-Lüneburg as well as Duke of Cumberland and Teviotdale, in the Peerage of Great Britain and Earl of Armagh, in the Peerage of Ireland, on 18 November 1851, assuming the style George V.[6] From his father and from his maternal uncle, Prince Charles Frederick of Mecklenburg-Strelitz, one of the most influential men at the Prussian court, George had learned to take a very high and autocratic view of royal authority.

Unlike his father, the King had a deep aversion to Prussia, which bordered on the Kingdom of Hanover in the west and east.

[8] Despite previously having concluded that Hanover could not win an armed confrontation with Prussia, George remained protective of his throne and refused the ultimatum.

As a result, the 20,600-strong Hanoverian Army surrendered on 29 June 1866 following the Battle of Langensalza, although tactically successful but hopelessly outnumbered in soldiers.

Austria lost the war and several of its Central German allies were annexed by Prussia, such as the Electorate of Hesse and the Duchy of Nassau.

George firmly rejected an abdication in favour of his son Ernest Augustus, as suggested by Queen Marie in order to be able to possibly save the existence of the Kingdom.

While the Austrian Emperor Franz Joseph I successfully campaigned for the continuation of the Kingdom of Saxony at the Prague peace negotiations, he did nothing to prevent the annexation of Hanover.

From 1866 to 1870, George V maintained the Guelphic Legion partially at his own expense, hoping that a Franco-Prussian war would lead to the reconquest of his kingdom.

After a funeral service in the Lutheran Church at the Rue Chaucat,[13] his body was removed to England and buried in St George's Chapel at Windsor Castle.