Ferdinand provided his allies with passive support but no enthusiasm, and after he witnessed a year of resounding victories by the French, he became the first member of the coalition to give up.

[3] His normalization of relations with France helped stabilize his rule for several years but by 1799 he was compelled to flee to Vienna for protection when republicans established a new government in Florence.

He was forced to renounce his throne by the Treaty of Aranjuez (1801): Napoleon brushed him aside to make way for the Kingdom of Etruria, created as compensation for the Bourbon Dukes of Parma, dispossessed by the Peace of Lunéville in that same year.

On 25 December 1805, Ferdinand had to give up Salzburg as well, which by the Treaty of Pressburg was annexed by his older brother, Emperor Francis II.

Two decades later, in Florence on 6 May 1821, Ferdinand married again, this time to the much younger Princess Maria Ferdinanda of Saxony (1796–1865).