The republican spirit in France after 1870 did not prevent Proust’s characters from enjoying the hospitality of La Duchesse de Guermantes. The German constitution of 1919, which abolished the Hohenzollern monarchy, did not forbid the Hohenzollern – or any member of the other German nobilities – to carry their titles, nor did they have to give up their properties.
Still, there is a rather important difference between Prince William, a real heir to the throne, and Prince Georg Friedrich Ferdinand von Hohenzollern, who is only a virtual heir to the throne. The difference is that the Hohenzollern throne does not exist.
Prince Georg Friedrich Ferdinand is the grandson of the grandson of Kaiser Wilhelm II, who abdicated in 1918. He is now the head of the House of Hohenzollern, his older brother having lost that position because he married a commoner. Most European monarchs – including the British – are allowed to marry commoners, vide Prince William. But the Hohenzollern are not if they want to be in line of the virtual succession.
Last Thursday, Prince Georg married Princess Sophie of Isenburg. All Frankfurters know Isenburg, a small Hessian town south of the Stadtwald, the municipal forest. Few have heard of the Isenburg nobility. But evidently she passed the Hohenzollern test, which is all that matters. The civil ceremony took place in Sans Souci, the delightful rococo castle Frederick the Great built in Potsdam as his summer residence. Bride and groom have known each other since childhood. Both are described as consultants and/or business managers.
The event had special meaning because this year the House of Hohenzollern is observing its 950th anniversary.
Lord Nicholas Windsor, the youngest son of the Duke of Kent, and Lady Nicholas (born Countess Paola Doimi di Delupis), representing the groom’s English relatives, were among the seven hundred guests. Prince Georg, like Lord Nicholas, is a direct descendent of Queen Victoria. According to legend, she died in 1901 in the arms of her favorite grandson, the Kaiser. The legend may have been manufactured by the Kaiser himself who once said that the only country in which he felt really at home was England. Queen Victoria could hardly have anticipated that less than twenty years after her death a considerable number of London papers vociferously demanded to “Hang the Kaiser!”
One may be sure this was not a sentiment many celebrants in Frederick the Great’s enchanting castle chose to remember last Thursday.
Sans Souci, in rough translation, means “no problem.”
Eric Koch’s book, The Weimar Triangle, is available at Indigo-Chapters and in your local bookstore. 
So who is the governing authority over the House of Hohenzollern with the power to decide whether the spouse of a blood-member of the family is sufficiently noble to permit the member to continue to be the head? What power have they to require that the member who marries a commoner must step down as head? Is this self-enforcing, so that the new groom’s elder brother resigned himself, in both senses of the word, in marrying his common (but otherwise no doubt lovely and appealing) spouse. For that matter, what are the duties of the head of the House, besides producing heirs to the virtual throne?
950 years as Hohenzollerns – how many as rulers of something? The same? The Maharana of Mewar in India claims to be the head of the oldest ruling family in the world, currently at 977 years and counting: “custodianship unbroken since 734 A.D.” . http://www.eternalmewar.in/Index.aspx
Were they mere Niederzollerns before?
No.
These excellent questions should be addressd to the House of Hohenzollern.
I do not think the head of the house of Hohenzollern has any duties. Correct me if I am wrong.
I am in no position to correct you since I have no connection with them. I assume one of their duties is to remember the birthdays of all the many princes and princesses to whom they are related and send them cards with litttle crowns on them.