On 7 April 1848, Mazzini reached Milan, whose population had rebelled against the Austrian garrison and established a provisional government. The First Italian War of Independence, started by the Piedmontese king Charles Albert to exploit the favourable circumstances in Milan, turned into a total failure. Mazzini, who had never been popular in the city because he wanted Lombardy to become a republic instead of joining Piedmont, abandoned Milan. He joined Garibaldi's irregular force at Bergamo, moving to Switzerland with him. Mazzini was one of the founders and leaders of the Action Party, the first organized party in the history of Italy.