I just found a Daily Telegraph obituary of Empress Zita (15 March 1989) & some of it I thought was v. interesting:
"...She shared the historic throne of the Holy Roman Empire; she was crowned Queen of Hungary in Budapest with her husband beside her wearing St. Stephen's Crown as Apostolic King....
The distinction frequently attributed to the Empress Zita of being the last European Empress belongs, however, to Queen Elizabeth, the Queen Mother, one-time Empress of India.
....Her links with European historythrough her parentage were as remarkable as those of her own life.
Her father reigned as Duke of Parma from 1854 to 1859 when the Duchy was still an independent state, before the unification of Italy. Her maternal grandfather Dom Miguel, usurped the Portuguese throne in 1828, causing the conflict known as the Miguelite War or the 'war of the brothers' - in which he had the sympathy of the British Prime Minister, the Duke of Wellington, who had seen him out with the Buckhounds, when staying with George IV at Windsor, taking 'his fences like anyone else.'
Princess Zita's aunt, Dona Maria das Neves, was married to one of the Carlist pretenders to the Spanish throne and fought in the Second Carlist War. Her eldest half-sister, Maria Luisa, was the first wife of 'Foxy Ferdinand' of Blugaria.
The other consort of a reigning monarch among her siblings belongs to much more recent history: her younger brother Prince Felix, who married the Grand Duchess Charlotte of Luxembourg.
Princess Zita....grew up to be of exceptional beauty and intelligence; it came as no surprise then when in 1911, at the age of 19, she married Europe's greatest Catholic royal parti, the 24 year old Archduke Karl...It was a love match; in falling in love with an eligible princess, Karl differed from most Hapsburgs of the previous generation....
...The Emperor Karl's peace attempt of 1917, in which the Empress Zita's brother, Prince Sixte of Bourbon Sicily acted as intermediary, was the only serious effort to end the war, made by any of the belligerent powers...Had it succeeded millions of lives would have been saved...At the same time as he worked for peace, the Emperor Karl set about reconstructing his heterogenous empire on federal lines, so that he became known as the 'Peace Emperor' & 'Emperor of the People.'
...[After Karl's death, Zita] travelled frequently; towrads the end of her life she paid her first visit to Austria since the fall of the monarchy & was given a tumultuous reception. She also paid 2 visits to Rome, being on cordial terms with Pope John Paul II, whose father had not only been a subject of the Emperor but had been commissioned by him in the Kaiserlich und Koniglich Army. "