in 1700, the Emperor proclaimed Milan a vacant Imperial fief and added it to his direct Austrian dominions in 1707 (confirmed by the Treaty of Rastatt at the end of the War of the Spanish succession); the Gonzaga of Mantua were deposed at the Diet of Regensburg in 1708 on charges of felony towards the Holy Roman Emperor and their state incorporated into Austrian Milan; following the extinction of the Florentine House of Medici in 1737, Francis I of Habsburg-Lorraine was invested with the Grand Duchy of Tuscany by Imperial diploma; a similar use of Imperial rights allowed the Habsburgs to establish dynastic branches in Parma and Modena. Emperor Leopold I increasingly asserted his rights over the imperial fiefdoms of Italy from the 1660s with the decline of Spanish power and more overt intervention of the French. In 1687, a new plenipotentiary of Italy was appointed, a position that had been left vacant for over a century prior (the powers of the office had instead been exercised haphazardly by the Aulic Council). In 1690, Prince Eugene tried to levy an imperial tax over Italy to pay for war expenses, the first time such a thing had been done. Then, in 1696, Leopold issued an edict mandating all of his Italian vassals to renew their oaths of allegiance within a year and a day on pain of forfeit. The renewal of fiefdoms incensed the papacy, some of whose own vassals now dug out ancient documents ostensibly proving them to be vassals of the Emperor. Smaller states of Italy saw the Emperor as their protector against larger territories like Savoy and the papacy. Imperial authority strengthened throughout the 18th century, with Lombardy (Milan and Mantua) passing to the Habsburg family as vacant imperial fiefs during the War of the Spanish Succession, the end of the War of the Quadruple Alliance reconfirming the statuses of Tuscany, Modena-Reggio, and Parma-Piacenza (Emilia) as imperial fiefs, and the Habsburgs continuing to rule the Italian territories of their hereditary lands (roughly the modern provinces of Trentino-Alto Adige and the Austrian Littoral). Piedmont-Savoy, on the other hand, remained defiant of Imperial authority despite officially participating in the diet and the duke receiving the title of "Royal Highness" from the Emperor in 1693. Dissolution The status of Imperial Italy was more or less stable up to 1789. There was even a serious push by the Savoyards (backed by Prussia)