While staying with Archduke Franz Ferdinand of Austria, Siegfried met his host’s unmarried half-sister, Archduchess Maria Annunciata, fell in love with her, and their engagement was to be announced in due course.

They would have made a comely couple, for the Princess had inherited much of the brilliance as well as good looks of her mother, the beloved Archduchess Maria Theresa, while Duke Siegfried was probably the best looking Prince of his house, a dashing cavalier, and one of the few scions of old world royalty and who had achieved distinction as a steeplechase rider.

[2] The breaking off of the engagement was a matter which was arranged between the young people themselves, and that they had been deeply in love with each other was shown by the appeal immediately afterward by the Archduchess to the Emperor for permission to enter a canonry for daughters of aristocratic families, yet without any vows, while the Duke became prey to melancholia, which in due course developed into insanity, rendering it necessary for his permanent confinement from 1906.

King Ludwig, after being placed under restraint as a lunatic, died a violent death in the waters of Lake Starnberg in 1886, while his former fiancée, after a far from happy marriage with the French Duke of Alençon, perished in the flames of the charity bazaar conflagration at Paris in 1897.

There is no evidence that Emperor Franz Joseph I of Austria declined to allow his niece to become a nun, pointing out to her that she should be content with her office of Abbess of the Order of Noble Ladies of the Hradschin at Prague, which was a sort of semi-ecclesiastical dignity invariably held by a Princess of the Imperial house.