Archduke Felix of Austria (given names: Felix Friedrich August Maria vom Siege Franz Joseph Peter Karl Anton Robert Otto Pius Michael Benedikt Sebastian Ignatius Marcus d'Aviano; 31 May 1916 – 6 September 2011) was the last-surviving child of Charles I, the last Emperor of Austria, and a member of the House of Habsburg-Lorraine.

Originally exiled in Switzerland the Imperial Family were taken to Portuguese island of Madeira in 1921 after Archduke Felix's father's failed attempts to claim the throne in the Kingdom of Hungary from the regent Miklós Horthy.

In the autumn of 1937, Archduke Felix was permitted to return to Austria, entering the Theresian Military Academy in Wiener Neustadt.

However, the battalion was disbanded when a number of exiled Jewish volunteers who made up the majority of the force ultimately declined to confirm their enlistment.

[10] Ultimately, a deal was reached between Felix, his brother Carl Ludwig and the Austrian government whereby they declared their allegiance to the republic without any reference being made to their rights to the throne or to their membership in the Imperial Family.

As they all lived in Mexico, and some still do, they are called by the Spanish equivalent of their names:[15] Along with his brothers Otto and Rudolf, Archduke Felix was a patron for the revived Almanach de Gotha.