After August 1859, the pro-Piedmontese regimes of Tuscany, Parma, Modena and the Papal Legations agreed to several military treaties.

During this time, Napoleon III faced pressure from Austria through their ambassador Richard von Metternich to halt Sardinian expansion[2] and restore Ferdinand IV (who had been deposed) as Grand Duke of Tuscany.

[2] The Austrians viewed Savoia-Carignano, a member of the same dynasty as Victor Emmanuel II, as presenting an unacceptable risk of promoting annexation by Sardinia.

[3] [3] At the urging of Napoleon III, Victor Emmanuel II refused to allow Savoia-Cariagnano to accept a position of leadership in Tuscany,[3] instead sending Carlo Bon Compagni[4] as the Governor General of Central Italy, and making him responsible for the diplomatic and military affairs of the states.

On 8 December 1859, Parma, Modena and the Papal Legations were incorporated into the Royal Provinces of Emilia.