Prussia invaded Hanover and Saxony on the 16th of June, and declared war with Austria on the 21st, one day after the Italian declaration of war had been delivered to the Archduke Albrecht. On the 23rd La Marmora's army began to cross the Mincio. It consisted of three _corps d'armée_ under the command of Generals Durando, Cucchiari and Delia Rocca, each corps containing four divisions. The force under Cialdini was composed of eight divisions forming one _corps d'armée._ An Italian military writer rates the numbers at 133,000 and 82,000 respectively. La Marmora acquired the belief that the Archduke's attention was absorbed by Cialdini's movements on the Po, and that his own operations on the Mincio would pass unobserved. While the Italian commander had no information of what was going on in the enemy's camp, the Archduke's intelligence department was so efficient that he knew quite well the disposition of both Italian armies. Cialdini's advance, if he meant to advance, was checked by floods. On the night of the 23rd most of La Marmora's force bivouacked on the left (Venetian) bank of the Mincio. No reconnaissances were made; everyone supposed that the Austrians were still beyond the Adige, and that they intended to stay there. The King slept at Goito. Before the early dawn next morning the whole Italian army of the Mincio had orders to advance. The soldiers marched with heavy knapsacks and empty stomachs, and with no more precautions than in time of peace. The Austrian Archduke was in the saddle at four a.m., and watched from an eminence the moving clouds of dust which announced the approach of his unsuspecting foe. La Marmora's intention had been to occupy the heights of Santa Giustina, Sona and Somma Campagna, but the Archduke anticipated his design, and while the Italians were moving from the Mincio, the Austrians were ranging themselves in those positions. At half-past five on the midsummer Sunday morning, the Austrian advance guard led by Colonel Pulz came up with Prince Humbert's division near Villafranca. The battle began dramatically, with a charge of the splendid Polish and Hungarian Hussars, who dashed their horses against the Italian squares, in one of which, opportunely formed for his shelter, was the gallant heir to the throne. Bixio's division was also engaged in this prelude, which augured not ill for the Italians, since at about eight o'clock Pulz received the Archduke's orders to retire.