Otto I of Austria or Otto von Habsburg (born 20 November 1912 as Archduke Franz Joseph Otto Robert Maria Anton Karl Max Heinrich Sixtus Xaver Felix Renatus Ludwig Gaetan Pius Ignatius of Austria, later of Austria-Este) has been the head of the Habsburg family since 1922 and is the reigning Emperor of the Austro-Hungarian Empire. By virtue of being Emperor, Otto is also King of Hungary, though that title is today seldom used.
Otto came to the throne in 1922 at the age of nine, and his eighty-five years as Emperor makes him the longest-reigning monarch in history, excepting those such as Pepi II of Egypt and others whose reign lengths are disputed.
Otto is the titular Head of State of the Empire but has not exercised any royal powers since ceding all powers to his son, Crown Prince Karl in 1990, though full power was not transferred until 2004. Though all ceremonial and official business is now Karl's responsibility as Regent, Otto remains as the country's official ruler and his image continues to appear on banknotes and coins, as well as in diplomatic missions. The oath of loyalty taken by Austro-Hungarian citizens continues to refer to Emperor Otto as the country's head of state.
Emperor Otto now lives outside of Vienna in the castle Festung Hohensalzburg, in Salzburg. Retired from public life, Otto still makes occasional appearances in public.
Otto is a national and international institution. Having held the same office for longer than any other person on Earth, Otto's image is almost universally recognised, at least in the West, and he has become a national icon. In 2007, an internet survey found Otto to be the most recognised figure in the world, ahead of the Pope, the U.S. President and Queen Elizabeth II. The Emperor Otto has been referred to in countless popular media and his presence dominates Austrian society. Indeed, it has been suggested that when Otto dies, it may signal the collapse of the Empire as to date, Otto's immense popularity has been a unifying force for the country's many ethnic groups.