Early in March the existence of the hitherto hidden army was revealed by an order for its advance toward Zurich to prepare for crossing the Alps. Switzerland, having fallen into French hands through Masséna's operations of the previous year, and being therefore no (p.~165) longer neutral, its territory was open for use in offensive operations against the foe. Masséna had received his first instructions a few days earlier. They were to concentrate the Army of Italy in order to defend Genoa and the entrance to France. Melas would surely follow the well-worn Austrian plan of advancing in three columns for a concentric attack. The French general was to avoid two, and meet the third with all his strength. In April, however, he was informed of the new combination, and told to stand on the defensive until the reserve army had crossed the Alps. "The art of war," Bonaparte always said, "is to gain time when your strength is inferior." This Masséna, with brilliant capacity, undertook to do when, on April sixth, the brave and veteran Melas attacked him with sixty thousand men. But in spite of repeated successes against superior numbers, before the end of the month active resistance became impossible, and the whole French center was compelled to withdraw on April twenty-first behind the walls of Genoa, the situation of which now became precarious, for it was blockaded by the English fleet, and provisions were growing very scanty, not more than sufficient stores for a month being available. Suchet, with the left of Masséna's army, ten thousand strong, retreated along the coast, pursued by Melas with twenty-eight thousand, until on May fourteenth the former crossed the Var. Ott, with twenty-four thousand men, was left to beleaguer Genoa, in which Masséna held out until June fourth--a siege considered one of the most stubborn in history. Such had been the wretched management of the previous year in the department of war at Paris that Moreau's force was not properly supplied in any particular, and he would not move until a month after the time arranged. It was not until April twenty-fifth, (p.~166) after an urgent request from Bonaparte, that he ventured to carry out his own cautious plan for the passage of the Rhine in four divisions instead of in one united body, as the First Consul had suggested. Less was risked, and probably less was won; but the complicated movement was prosperous. Making a feint as if to occupy the Black Forest, he completely misled Kray as to his real intentions, and induced him to abandon his strong position at Donaueschingen. By a series of clever countermarches, in which the Rhine was crossed and recrossed several times by various French corps, the whole of Moreau's command was finally united beyond the Black Forest, having successfully outflanked not only that dangerous mountain-range, but also the enemy, which was still occupied in guarding its eastern exits.