One source of confusion is the question of whether the "Mrs. Royals" system has applied to titles outside the UK. It's common knowledge, for instance, that the woman born as Baroness Marie-Christine von Reibnitz has always styled herself as "HRH Princess Michael of Kent" -- not "HRH Princess Marie-Christine of Kent". After all, she is not a British princess by birth, like her sister-in-law (HRH Princess Alexandra of Kent). So it's only right that she uses her husband's given name with the Princess title.
My understanding is that Archduchess Maria Theresia of Austria-Este actually styled herself in Bavaria, after marriage, as Princess Ludwig: the reason was to avoid confusion with her unmarried sister-in-law, Princess Theresa.
The wife of Prince Luitpold's youngest son, Prince Arnulf, had an even better reason for styling herself by her husband's name, since her birth name was Theresa, not Maria Theresa. Like the Habsburg archduchesses (the middle son, Prince Leopold, married Gisela of Austria), she was a Wittelsbach by marriage, not birth, as she had been born a princess of Liechtenstein. Given all these facts, she understandably was styled as "HRH Princess Arnulf of Bavaria."
Anyhow, bearing all this in mind, I was wondering if anybody can identify everybody (hope the link works) --