Guillaume du Tillot was again used during Ferdinand's reign when he lost his father in 1765 aged 14. Negotiations and ideas were passed from Vienna to Parma and in 1769, Ferdinand was to marry Archduchess Maria Amalia of Austria; the eighth child of the Empress and older sister of the Queen of Naples and Sicily and the future Queen of France. Maria Amalia had a marriage by proxy in Vienna on 27 June and left her home on 1 July. The future duchess would meet her husband at Mantua on 16 July. His wife was with her brother Joseph II, Holy Roman Emperor and Ferdinand with members of the Sforza family. On 19 July there was a formal ceremony for all at the Ducal Palace of Colorno where Ferdinand had been born. During many festivities, the couple made their official entrance to Parma on 24 July. They had nine children in just under twenty years.