How did Lombardy become part of Piedmont after the war of 1859?

Following the Second Italian War of Independence in 1859, the transfer of Lombardy to Piedmont was a result of military conflict and subsequent diplomatic negotiations between France, Austria, and Piedmont.

During the war, French and Piedmontese forces achieved victories against Austria at the Battle of Magenta and the Battle of Solferino. Following these engagements, French Emperor Napoleon III unexpectedly signed an armistice with the Austrian Emperor Francis Joseph at the Conference of Villafranca in July 1859.123

Under the terms of this preliminary peace, Austria ceded Lombardy—excluding the fortress cities of Mantua and Peschiera—to France, which then transferred the territory to Piedmont. These terms were later formalized in the Peace of Zurich in November 1859. While the acquisition of Lombardy was a significant step in the unification of Italy, the outcome disappointed Italian nationalists because Venetia remained under Austrian control.123