Otto Habsburg-Lothringen, the eldest son of the last Austrian emperor who became a champion of European unity, died aged 98 at his home in Germany on Monday, his family said.
“He died peacefully with his family present,” a man who identified himself as a grandson said by telephone from Poecking on Lake Starnberg in southern Germany, where Habsburg had lived since 1954 during a life spent mostly in exile.
Born in 1912, the man also known as Archduke Otto von Habsburg became head of the imperial House of Habsburg on the death of his father, Charles, in 1922.
The Habsburgs were the ruling family of the Austro-Hungarian empire, which collapsed at the end of World War One.
Austria abolished the monarchy and seized Habsburg property in 1919, shortly after the family fled to Switzerland.
Habsburg also lived in Portugal, Spain, Belgium, France and the United States before settling at Villa Austria on Lake Starnberg in Bavaria more than half a century ago.
He officially relinquished his claim to the throne in 1961 and was allowed to return to post-war Austria only in 1966after years of political and legal jousting.
He had been a member of the European Parliament for the German state of Bavaria and lectured throughout the world on international affairs.
An opponent of the Nazis who criticised Germany’s annexation of Austria in 1938, Habsburg joined the Paneuropean Union movement and took up the cause of former subjects in eastern Europe oppressed during communist rule.
He withdrew from public life after his wife, Princess Regina von Sachsen-Meiningen, died last year. They had seven children.
His coffin will remain for three days in a church in Poecking, followed by requiem services in Munich, Vienna, Budapest and elsewhere, his website said.
Former Austrian Chancellor Wolfgang Schuessel called him “a great Austrian patriot” who “incorporated pan-European thinking like no other and articulated this already at a time when a dark shadow hung over the continent”.
“Austria has lost a great statesman,” far-right politician Heinz-Christian Strache said.