A little trivia
In the next to last episode; when the Archduke is assassinate in Sarajevo and war is declared (World War I) there is a short segment which shows a young family seated at an outdoor restaurant. The man (husband) was Karl,an Austrian army Captain (I think that was his rank) who was the grandnephew of Franz Joseph and was thereby "promoted" as he came after the Duke in the line to the Hapsburg throne. The assassination put him next to Emperor Franz Joseph, who was a very elderly man even then.
Anyway, also at the table is shown the man's wife. That is the portrayal of Zita; she became Emperoress when Karl became Karl the 1st a couple of years later after Franz Joseph died. Zita was still alive when "Fall of Eagles" was made; and, I believe she was the only portrayed individual who was still alive during the filming.