emperor (Kaiser) of Austria and, as Charles IV, king of Hungary, the last ruler of the Austro-Hungarian monarchy (Nov. 21, 1916–Nov. 11, 1918).

A grandnephew of the emperor Francis Joseph I, Charles became heir presumptive to the Habsburg throne upon the assassination of his uncle Francis Ferdinand (June 28, 1914), whose children were barred from succession because of his morganatic marriage. After his accession, Charles, a peace-loving man, made attempts to take Austria-Hungary out of World War I through secret overtures to the Allied powers, the most promising being through his brother-in-law, Prince Sixtus von Bourbon-Parma. All failed, largely because the emperor refused to cede any territories to Italy. Because he had also supported French claims to Alsace-Lorraine, his reputation both in Germany and at home suffered when his efforts were made public.

World War I accelerated the centrifugal forces of nationalism in Charles's multinational empire. His solution, transformation of the western part of his empire into a federated state, announced in October 1918, proved insufficient and too late. On Nov. 11, 1918, after the collapse of the Austro-Hungarian armies on the Italian front, Charles renounced all participation in affairs of state but did not abdicate. Exiled to Switzerland in March 1919, he was deposed by the Austrian parliament that April. In 1921 he twice tried to regain his Hungarian throne but failed and was sent to exile in Madeira, living there in very poor conditions and dying of pneumonia.

Upon Charles's death in 1922, his widow, Zita von Bourbon-Parma (1892–1989), went into mourning and wore black for the rest of her life, dying at age 96 in Switzerland.