Of course, Franz Ferdinand is known to history for his assassination in Sarajevo which sparked the First World War in 1914. On a personal level he was luckier with his marriage but, considering that he was the heir to a vast Empire he was unlucky in falling in love with a woman who not only could not share his status but was also bullied by the Austro-Hungarian Court.
Although descended through the female line from the Habsburgs, Sophie Chotek was of noble birth rather than dynastic royal birth. Therefore, any marriage between Sophie and Franz Ferdinand would be deemed what is call morganatic - of unequal status. Sophie would never become Empress Consort and their children would not be heirs to the Throne. Such was their love, however, that Franz Ferdinand agreed to the marriage going ahead on that basis and made an Oath of Renunciation on 28th June 1900.
Sophie was not allowed to join her husband at royal functions as she ranked behind every other Archduke and Archduchess. Franz Josef did concede somewhat by raising Sophie to the title of Duchess and the rank of Highness. However, that didn't prevent her from having to enter a room on the arm of the last Archduke. Not only that, the court officials would make sure that the door on her side was discretely closed in her face, forcing her to go through sideways.
When Franz Ferdinand's nephew, Karl, came to the Austrian Throne in 1916 on the death of Emperor Franz Josef, he transferred the Este title to his second son Robert. Karl's wife Zita was herself descended from previous Dukes of Modena. Robert passed away in 1996 and the title was inherited by his son, Lorenz, who is married to HRH Princess Astrid of Belgium. Their children are known as Archduke/Archduchess of Austria-Este and Prince/Princess of Belgium. Their eldest son and the heir to the Este title is HI & RH Prince Amedeo of Belgium, Archduke of Austria-Este, born in 1986.
Sophie's Coat of Arms shows her paternal Arms with Franz Ferdinand's simple Austrian dynastic Arms (minus Este) on an Inescutcheon. Chotek was a Czech noble family in the Kingdom of Bohemia. The original Chotek Coat of Arms is represented on the lower Inescutcheon, namely a Shield split in two with the upper half split white and red and the lower half with half a white Wheel on red. In 1685, the Coat of Arms of the Chotek family had been joined with the Coat of Arms of the extinct Charwat von Bärnstein family. These were the Augmentation Arms of the Holy Roman Empire (a black, double-headed Eagle on yellow) quartered with a yellow Bear (Bär in German) on blue. The family's Supporter's were two golden Bears.
On 13 May 1743 in Laxenburg, Václav Antonín Chotek of Chotkov and Vojnín was awarded the title of Count (Graf, hrabě) in Bohemia. On 4 October 1745 in Frankfurt am Main, he was elevated to the rank of Reichsgraf (Imperial Count), hence Sophie's noble title.
Strangely enough, the representation at the time of Sophie's marital Coat of Arms shows what seems to be an Imperial Crown. It is, in fact, a ducal Crown! The Crown for an Archduke, such as Franz Ferdinand, did not have the red lining that a ducal Crown did...
The joint visit took place on 28th June - the very anniversary of Franz Ferdinand's Oath of Renunciation...
Franz Ferdinand was looked on as a reformer and therefore a troublemaker in the eyes of the Establishment. The next in line, Karl, with his royal-born wife Zita, was looked on as a better, more compliant heir. Little did they know what Zita would get up to...
POSTSCRIPT: I am indebted to a regular follower for pointing out that the component Arms for Franz Ferdinand which I took to be Dalmatia (the black crow) are, of course, Galicia. The red and white bars on blue represent Galicia's sister Kingdom of Lodomeria. Both were Crownlands of the Hapsburg Monarchy.
Many thanks.