The parliamentary session that ran was the final session of the Sardinian-Piedmontese parliament. The next session, running from 18 February 1861 till 7 September 1865, would be the first such session in the new Kingdom of Italy. Mordini was present early in June 1860 for the vote to approve the transfer of &lt;a href="Nice"&gt;Nizza/Nice&lt;/a&gt; - hitherto a territory of Sardinia-Piedmont - to the French Empire. This was part of in the recent war against Austria. Mordini voted against the motion. After that he was absent from the chamber for the rest of the parliament. A few days after the vote on Nice/Nizza he joined the so-called Expedition of the Thousand, a volunteer army organised by Giuseppe Garibaldi in order to capture the Kingdom of the Two Sicilies as part of the still incomplete unification project. Garibaldi had been born in &lt;a href="Nice"&gt;Nice/Nizza&lt;/a&gt;, and would never forgive the perfidious Sardinians for having given away the city of his birth as part of the price for securing French support in the recent war of independence against the Austrians. He was no doubt appreciative of Mordini's action in having voted against the sacrifice. He was also an admirer of Mordini's skills as a political operator. The conquest of Sicily was accomplished during the summer. On 20 June 1860 Garibaldi promoted Mordini to rank of lieutenant colonel and appointed him the presidency of the "War Council" ("Tribunale militare" or, sometimes, "Consiglio di guerra"), based in Palermo. Further promotion followed. On 3 September 1860 he was appointed "auditore generale militare" ("loosely, "army auditor general"") which came with membership of Garibaldi's "general staff" team. That turned out to be no more than a stepping stone, however: on 17 September 1860 Antonio Mordini was appointed interim governor ("prodittatore" - loosely "acting dictator") of Sicily following the resignation of Agostino Depretis, the previous incumbent.