The Carthaginian army has a mix of all kinds of troops, because of his high proportion of, Spanish and African allies.
The Carthaginians relied heavily on mercenaries. Polybius (6.52.4) believed the Roman army was superior to the Carthaginian because Rome fielded armies of citizens while Carthage employed foreign mercenaries. The most famous mercenaries employed by the Carthaginians were the Numidian horsemen. Equipped with light leather shields (Sall. Iug. 94.1), they would sometimes fight from two horses, to prolong the stamina of their mounts (Livy 23.29.5). However, in its earlier wars with the Greeks, Carthage relied also on its own citizen forces. Plutarch (Tim. 27-9) notes that at the battle of the River Crimisus in 341, the 10,000 Carthaginian hoplites were equipped with iron cuirasses, bronze helmets and large whiteshields, and were drawn up as a phalanx in 400 files each twenty-five deep. The elite unit of the army was the Sacred Band, numbering 2,500 (Diod.’Sic. 16.80.4). This suggests the infantry was organized in units of 500 men.
Chariots were also used by the Carthaginians. They are first mentioned at the battle of the Crimisus River in 341. Like Seleucid chariots they were quadrigas and were drawn up in front of the main line (Plut. Tim. 25.1,27.2).Elephants were employed by those Hellenistic armies able to procurethem. 91 At first, the elephant was ridden by a mahout and one or two warriors. Later on, elephants were fitted with towers which offered protection to the crew, and the elephants themselves were increasingly armoured.
The Carthaginians adopted war elephants in place of their outdated chariots, probably after suffering at the hands of Pyrrhus’ beasts. Elephants became perhaps the most distinctive feature of battles in this era.
Carthage, with her new resources and territorial dominions, was once again at least as powerful as Rome. The Romans with their Italian allies could call on about three-quarters of a million men of military age, in a total population of three to four million. Carthage with her chora, allies and subjects from Lepcis Magna to Gades will have had a population roughly similar. In 218, according to Hannibal’s own figures (so they seem from Polybius’ account), she put into service some 122,000 troops, while Rome’s field armies totalled 71,000. Nor was any Roman general of the day – or the first decade of war – any match for Hannibal. Two drawbacks did exist: the fleets in both Spanish and African waters were puny compared with Rome’s 220 fully-equipped warships; and none of the other Carthaginian commanders in the entire war, even Hannibal’s brothers, proved better than the enemy’s.
Hannibal had expected war before the Romans declared it. He readied a large army to invade Italy: for the alternative, to wait for them to attack him in Spain – and invade Libya too – was out of the question. The first years of his Italian expedition are by far the best known, marked by his crossing of the Alps and three great victories over one Roman army after another: at the river Trebia in December 218, Lake Trasimene in June the year after, and Cannae in Apulia in August 216 which put most of central and southern Italy at his mercy. The brilliance of these victories has made his reputation immortal – the only Carthaginian, indeed, with a name still instantly recognisable. Much of southern Italy changed sides to ally with him after 216, so that Carthage by 212 had Rome hemmed in on almost every side.
Besides these new supporters, she had as allies the Numidian kings, the Gauls in northern Italy, Syracuse in Sicily, and the kingdom of Macedon across the Adriatic. She also controlled most of Spain. From late 216 to the middle of 207, Carthage was the greatest power in the western Mediterranean, facing a shrunken and tormented Rome.
This supremacy was not easily won or free of severe flaws. When Hannibal crossed the Pyrenees in mid-218, leaving his brother Hasdrubal in charge of Spain, he had 59,000 troops – but, after he arrived in northern Italy, only 26,000. The usual explanations for this staggering loss are attacks by the Gauls along the route and Alpine snow and ice; but in reality the Gauls’ off-and-on attacks, all told, amounted to just seven days’ fighting, while snow and ice were met only in the final week, on the pass and the way down to Italy. Supplies en route were plentiful, even in the autumnal Alpine valleys. Nor did he leave garrisons in Gaul. The likeliest explanation is that numbers of the Libyan, Numidian and Spanish troops simply deserted – both in southern Gaul, and later in north Italy before his roll-call. Luckily, the Gauls in north Italy had risen against their Roman conquerors and brought him valuable extra forces.
The Romans’ response from 218 to 216 was to confront the invaders head-on, in the normal way of Mediterranean warfare. It was Hannibal’s way, too. Alexander the Great had shown how a series of devastating victories could bring down even the most imposing enemy; after his three, Hannibal looked to the shattered Romans to talk. Their response, unconventional by Mediterranean great-power standards but entirely in line with their own responses to Pyrrhus and to their First Punic War disasters, was to refuse talks of any kind. Meanwhile they changed their military strategy.
Hannibal did have at least two opportunities to put crushing pressure on them, but avoided it. After Trasimene, the Romans and his own side expected him to march direct on Rome, only four days away for an army and fewer for cavalry. A fleet from Carthage sailed to the Etruscan coast to link up with him, only to find that he had swung east to the Adriatic. After Cannae a year later, with almost no Roman forces left in the field, he again chose not to advance on the city. Livy’s famous tale has his bold cavalry general Maharbal comment sourly that `you know how to win, Hannibal; you don’t know what to do with victory’. It was certainly impossible to take Rome by siege. Cutting it off from outside, though, was feasible especially when there were no organised Roman forces in the countryside to cause trouble, and could have been done as early as the aftermath of Trasimene. Like Mathos’ and Spendius’ mutiny at Tunes in 241, this could also – and perhaps decisively – have been the signal to all of Rome’s restive fellow-Italians to come over to the clearly dominant invader.