Charles I of Austria
Charles I or Karl I (Karl Franz Joseph Ludwig Hubert Georg Otto Maria; 17 August 18871 April 1922) was the last Emperor of Austria, the last King of Hungary (as Charles IV, ), the last King of Bohemia (as Charles III), and the last monarch belonging to the House of Habsburg-Lorraine. After his uncle Archduke Franz Ferdinand of Austria was assassinated in 1914, Charles became heir presumptive of Emperor Franz Josef. Charles I reigned from 1916 until 1918, when he "renounced participation" in state affairs, but did not abdicate. He spent the remaining years of his life attempting to restore the monarchy until his death in 1922. Beatified by Pope John Paul II in 2004, he is known to the Catholic Church as Blessed Karl of Austria.
Austria-Este
Although the first heir, Archduke Franz Ferdinand (1863-1914), was not a descendant of the last Este duchess, Mary Beatrice of Modena), he took the name Austria-Este. In 1896 he became the heir presumptive of the Austrian Empire and, according to the terms of the secundogeniture, could not combine the Austria-Este inheritance with that of the main line of the House of Habsburg (i.e., the Austro-Hungarian Empire, but he was assassinated 28 June 1914 in Sarajevo before becoming emperor. Because Franz Ferdinand's children were born in morganatic marriage (see House of Hohenberg), on 16 April 1917 Emperor Charles I of Austria, as head of the House of Habsburg, issued letters patent conferring the name, arms and patrimony of Austria-Este on his son, Archduke Robert, and his future issue according to masculine primogeniture. Through his mother Zita of Bourbon-Parma, Robert happened to be a descendant of Duke Ercole III of Modena as well, and thus the blood of the last Este dukes was joined with the name Austria-Este.