In 547, a great army, which had left Spain under the command of one of his brothers, Hasdrubal, had crossed the Alps, and was advancing to unite with him, marching along the coast of the Adriatic. Two consular armies were charged with the war against the Carthaginians: one, under the command of the consul M. Livius Salinator, in Umbria; the other, having at its head the consul C. Claudius Nero, held Hannibal in check in Lucania, and had even obtained an advantage over him at Grumentum. Hannibal had advanced as far as Canusium, when the consul Claudius Nero, informed of the numerical superiority of the army of succour, leaves his camp under the guard of Q. Cassius, his lieutenant, conceals his departure, effects his junction with his colleague, and defeats, near the Metaurus, Hasdrubal, who perished in the battle with all his army.[528] From that moment Hannibal foresees the fate of Carthage; he abandons Apulia, and even Lucania, and retires into the only country which had remained faithful, Bruttium. He remains shut up there five years more, in continual expectation of reinforcements,[529] and only quits Italy when his country, threatened by the Roman legions, already on the African soil, calls him home to her defence. In this war the marine of the two nations performed an important part. The Romans strained every nerve to remain masters of the sea; their fleets, stationed at Ostia, Brundusium, and Lilybæum, kept incessantly the most active watch upon the coasts of Italy; they even made cruises to the neighbourhood of Carthage and as far as Greece.[530] The difficulty of the direct communications induced the Carthaginians to send their troops by way of Spain and the Alps, where their armies recruited on the road, rather than dispatch them to the southern coast of Italy. Hannibal received but feeble reinforcements;[531] Livy mentions two only: the first of 4,000 Numidians and 40 elephants; and the second, brought by Bomilcar to the coast of the Ionian Gulf, near Locri.[532] All the other convoys appear to have been intercepted, and one of the most considerable, laden with stores and troops, was destroyed on the coast of Sicily.[533]