Who married Princess Amélie Louise of Arenberg?

Princess Amélie Louise Julie of Arenberg, (full German name: Amalie Luise Julie, Prinzessin und Herzogin von Arenberg and full French name: Amélie Louise, princesse et duchesse d'Arenberg, (born 10 April 1789 in Brussels, Austrian Netherlands; died 4 April 1823 in Bamberg, Kingdom of Bavaria) was a member of the House of Arenberg by birth and, through her marriage to Duke Pius August in Bavaria, a member of the Palatinate-Birkenfeld-Gelnhausen line of the House of Wittelsbach. Amélie Louise was the paternal grandmother of Empress Elisabeth of Austria through her son Duke Maximilian Joseph in Bavaria.