British people shared these high hopes, lining the streets despite the heavy January snowfall to cheer as Vicky departed for Prussia: “God Save the Prince and Bride!God keep their lands allied.” When Prince Albert died on 14 December 1861, his inconsolable wife and eldest daughter both felt charged with a renewed mission to carry out his wishes.

Their grand scheme began to take shape in the autumn of 1855, when Queen Victoria and Prince Albert invited the handsome second heir to the Prussian throne, Prince Frederick, to Balmoral.

Although their beloved oldest daughter, Vicky, was just 14, they had long planned a great dynastic marriage for her.

Vicky’s brilliant marriage to the future Prussian heir aimed at nothing less than to fashion the political development of Prussia-Germany along British lines and then to facilitate an Anglo-German alliance to keep the peace.

The young princess was to nurture the seed of enlightened, liberal thinking on Prussian soil and help steer the new state towards a parliamentary constitutional monarchy.

Each marriage was a form of soft power: a path to help spread British liberal values across the continent, and perhaps even push back against the destabilising forces of republicanism, revolution and war.

Prince Albert glimpsed the possibility of a federal Europe, in which a series of strong, independent countries, stable under their own constitutional monarchies (and ideally modelled as closely as possible on the British constitution), could be united by common goals and interests.

After the Napoleonic Wars, British foreign policy aimed to achieve a balance of power in Europe; no single country should become sufficiently dominant to unleash such destruction across the continent ever again.

In the mid-19th century, Prince Albert and Queen Victoria believed that dynastic marriages between their nine children and European royalty would provide a further safeguard.

Suitable dynastic matches had already been identified for Albert and Victoria’s next two children.