*The Roman plan of campaign.* The most fateful result of the First Punic War had been the destruction of the maritime supremacy of Carthage. She never subsequently thought of contesting Rome’s dominion on the sea, and consequently, while extending her empire in Spain and Africa she had neglected to rebuild her navy. This fact was to be of decisive importance in the coming struggle. Rome, relying upon it, planned an offensive war. One army, under the consul Publius Cornelius Scipio, was to proceed to Spain, supported by the fleet of Massalia, and to detain Hannibal there, while a second army, under the other consul, Tiberius Sempronius, was assembled in Sicily to embark for Africa. *The plan of Hannibal.* But the Romans had not taken into account the military genius of Hannibal, whose audacious plan of carrying the war into Italy upset their calculations. Realizing that he could not transport his army to Italy by sea, he was prepared to cross the Pyrenees, traverse southern Gaul and, crossing the Alps, descend upon Italy from the north. Among the Gauls of the Po valley he hoped to find recruits for his army, and expected that, once he was in Italy, the Roman allies would seize this opportunity of recovering their independence. Deprived of their support Rome would have to yield. His ultimate object was not the destruction of Rome, but the breaking up of the Roman federation in Italy, and the reduction of the Roman state to the limits attained in 340 B. C. This purpose is apparent from the plan of campaign which he followed after his arrival in Italy. *Hannibal’s march into Italy.* Hannibal’s preparations were more advanced than those of the Romans and, early in the spring of 218 B. C., he set out from New Carthage for the Pyrenees. Forcing a passage there, he left the passes under guard and resumed his march with a picked army of Spaniards and Numidians. His brother Hasdrubal was left in Spain to collect reinforcements and follow with them. Hannibal arrived at the Rhone and crossed it by the time that Scipio reached Massalia on his way to Spain. The latter, failing to force Hannibal to give battle on the banks of the Rhone, returned in person to Italy, but decided to send his army, under the command of his brother, to Spain, a decision which had the most serious consequences for Carthage. Meanwhile Hannibal continued his march and, overcoming the opposition of the peoples whose territory he traversed, as well as the more serious obstacles of bad roads, dangerous passes, cold, and hunger, he crossed the Alps and descended into the plain of North Italy in the autumn of 218, after a march of five months.(7) His army was reduced to 20,000 infantry and 6,000 cavalry. Practically all his elephants perished.