His maternal grandfather, King Maximilian I of Bavaria, had given Eugène the title "Duke of Leuchtenberg" on 14 November 1817, after the loss in 1815 of his Napoleonic titles and the associated expectancies of the Kingdom of Italy and the Grand Duchy of Frankfurt. Despite the promise of an independent principality inserted into the final treaty, the Congress of Vienna adjourned without creating a state for Eugène, so Auguste and his siblings had no inheritance. To the empty Leuchtenberg ducal title had been added the estate of Eichstätt in dowry, made a nominal principality, also by King Maximilian. Eugène's eldest son Auguste was heir to this modest property, which he inherited when Eugène died on 21 February 1824.