With war looming between Piedmont, Austria, and France, and with nationalist street demonstrations taking place all over Italy, Pope Pius IX issued an encyclical calling for public prayers for peace between Catholic nations. Two days later, Austria declared war on Piedmont. (By John Osborne)

With war looming, Italian nationalists began to demonstrate all over Italy. In Florence, this would lead to the overthrow of the Tuscan government. In Rome, though, Napoleon III could not afford to offend the Pope Pius IX and ordered General De Goyen, commanding the French troops already in Italy protecting the Papal States, to put down all street demonstrations. (By John Osborne)

On April 26 the French minister to Austria told the Austrian foreign minister that France would consider an Austrian crossing of the Ticino River into Piedmont as an attack upon France. In fact, French units had already moved toward Piedmont and by April 26 substantial French forces were in Turin. Three days later, the Austrian Emperor Franz Josef published his declaration of war and his troops did begin crossing the Ticino. (By John Osborne)