Second Punic War Begins; Hannibal Invades Italy

The Spanish engine Hamilcar built now powered his son’s audacity. As quarrels over Saguntum and pledges north of the Ebro sharpened, Hannibal chose movement over argument. In 218 BCE, he crossed the Pyrenees with a mixed army, then forced his way through the Rhône country and the Alps, descending into the Po valley with a force hard as the ice it traversed [5], [1]. Livy’s summaries chart the onset: Roman attention split between Iberia and Cisalpine Gaul; Hannibal exploited that dispersion, appearing where Rome least wanted—on the Italian side of the mountains [5]. The sounds were unfamiliar to local farmers: foreign tongues, the clatter of Iberian shields, the creak of overburdened wagons on frozen paths. The color in the passes was the dark of pine and the white of snow, broken by the scarlet of Carthaginian standards. The causation ran through the Ebro. Polybius’ diplomatic survey explains how Rome tried to fix a northern boundary and how the Barcids worked south of it [1]. When Saguntum, a Roman-aligned city south of the Ebro, fell, the legal argument tangled with the military one: Rome claimed violation; Hannibal claimed right. The result was not litigation but invasion. Hannibal’s army was a mosaic—Libyan spearmen from Africa, Numidian light cavalry, Iberian swordsmen from the Baetis, and a handful of elephants for shock. The route—New Carthage to the Pyrenees, along the Rhône, over the Alps—stitched together geography and resolve. In Rome, senators listened to the oarlocks creak at Ostia and wondered whether the fleets could cut Spain off in time. By year’s end, the war was fully joined. Battles at the Trebia and later at Trasimene and Cannae would announce the cost of underestimating an enemy who thought in roads and seasons, not just laws and lines.