Otto was born at Villa Wartholz in Reichenau an der Rax, Austria-Hungary.
He was baptised Franz Joseph Otto Robert Maria Anton Karl Max Heinrich Sixtus Xavier Felix Renatus Ludwig Gaetan Pius Ignatius on 25 November 1912 at Villa Wartholz by the Prince-Archbishop of Vienna, Cardinal Franz Xaver Nagl.
This name was chosen so that he might reign as “Franz Joseph II” in the future.
His godfather was the Emperor Franz Joseph I of Austria (represented by Archduke Franz Ferdinand of Austria); his godmother was his grandmother Infanta Maria Antonia of Portugal.

In November 1916, Otto became Crown Prince of Austria, Hungary, Bohemia and Croatia when his father, Archduke Charles, acceded to the throne.
However, in 1919, after the end of the First World War, the monarchies were abolished, the republics of Austria and Hungary were founded in their place, and the family was forced into exile in Madeira.
 Hungary did become a kingdom again, but Charles was never to regain the throne.
Instead, Miklós Horthy ruled as regent until 1944, in a kingdom without a king.

Otto spoke German, Hungarian, Croatian, English, Spanish, French and Latin fluently.
In later life, he would write some forty books in German, Hungarian, French and Spanish.
His mother made him learn many languages because she believed he one day might rule over many lands.
Otto was born at Villa Wartholz in Reichenau an der Rax, Austria-Hungary. He was baptised Franz Joseph Otto Robert Maria Anton Karl Max Heinrich Sixtus Xavier Felix Renatus Ludwig Gaetan Pius Ignatius on 25 November 1912 at Villa Wartholz by the Prince-Archbishop of Vienna, Cardinal Franz Xaver Nagl. This name was chosen so that he might reign as “Franz Joseph II” in the future. His godfather was the Emperor Franz Joseph I of Austria (represented by Archduke Franz Ferdinand of Austria); his godmother was his grandmother Infanta Maria Antonia of Portugal.
In November 1916, Otto became Crown Prince of Austria, Hungary, Bohemia and Croatia when his father, Archduke Charles, acceded to the throne. However, in 1919, after the end of the First World War, the monarchies were abolished, the republics of Austria and Hungary were founded in their place, and the family was forced into exile in Madeira.  Hungary did become a kingdom again, but Charles was never to regain the throne. Instead, Miklós Horthy ruled as regent until 1944, in a kingdom without a king.
Otto spoke German, Hungarian, Croatian, English, Spanish, French and Latin fluently. In later life, he would write some forty books in German, Hungarian, French and Spanish. His mother made him learn many languages because she believed he one day might rule over many lands.
Otto von Habsburg