The death of the duke opens the thorny question of the Austro-Hungarian succession.
The Archduke’s marriage with the Duchess of Hobenburg meant that his children according to Austrian law as already states were debarred from succeeding him in his rights to the Austrian throne, their disqualification however did not extend to the Hungarian part of the monarchy’s where the marriage was regarded as valid in every respect.
In these circumstances If a division of the monarchy had been possible the eldest son of the Archduke would have succeeded the Emperor Francis Joseph on the latter’s demise in Hungary while Archduke Karl Francis the son of Francis Ferdinand’s brother would have been Emperor of Austria in virtue of his seniority in the collateral male line.
It is said however in anticipation of the dynastic difficulty, Francis Ferdinand signed on the day of his marriage a voluntary abdication on behalf of his future children of their prospective rights to the exception in Hungary.
If true, this would appear to leave Archduke Karl Francis in sole possession of the title with rights of heir to the double throne, but it does not dispose of the point as to whether in view of the provisions of the law in Hungary, Archduke Francis Ferdinand could thus abandon the rights of his children.