Italy in 1848–49: The First War and the Roman Republic

In March 1848 the people of Milan rose against Austrian rule in the Five Days, driving out Marshal Radetzky's army, and Venice proclaimed a republic. King Charles Albert of Piedmont declared war on Austria, launching what Italians call the First War of Independence. Volunteers came from across Italy, but rulers were reluctant and cooperation was weak. Radetzky defeated the Piedmontese at Custoza in July 1848 and again at Novara in March 1849, after which Charles Albert abdicated in favor of his son, Victor Emmanuel II.

Meanwhile radicals proclaimed a Roman Republic in February 1849 after the Pope fled the city, with Mazzini among its leaders and Giuseppe Garibaldi defending it. French troops sent by Louis-Napoleon besieged and captured Rome in July 1849, and Venice surrendered in August. The failures convinced many that Italians could not defeat Austria alone and needed a foreign ally.