Zonaras 8,21
In the following year the Romans became openly hostile to the Carthaginians, and this war, though of far shorter duration than the previous one, proved to be both greater and severer in its exploits and its disasters. It was brought on chiefly by Hannibal, the general of the Carthaginians. This Hannibal was a son of Hamilcar Barca, and from his earliest boyhood had been trained to fight against the Romans. For Hamilcar said he was rearing all his sons like so many whelp[s to fight against them, and when he saw that this one had by far the best nature, he made him take an oath that he would wage upon them; accordingly he was engaged in giving him a careful training, particularly in warfare, at the time of his own death, when the boy was fifteen years of age. Because of his youth Hannibal was unable to succeed then to the generalship; upon the death of Hasdrubal, however, he delayed no longer, being now twenty-six years of age, but at once took possession of the army in Spain, and after being acclaimed general by the soldiers, brought it about that command was confirmed to him also by those in authority at home. After accomplishing this he required a plausible excuse for his enterprise against the Romans, and this he found in the Saguntines of Spain. These people, dwelling not far from the river Iberus, and a short distance from the sea, were dependents of the Romans, who held them in honor, and in the treaty with the Carthaginians had made a special exception of them. Hence, for this reason Hannibal began war with them, knowing that the Romans would either assist the Saguntines or avenge them if they suffered injury. From this motive, then, as well as because he knew that they possessed great wealth, which he particularly needed, and from various other considerations that promised him advantages against the Romans, he made an attack upon the Saguntines.
These Saguntines, then, upon being besieged, sent to their neighbors and to the Romans, asking for aid. But Hannibal checked any local movement, while the Romans sent ambassadors to him commanding him not to come near the Saguntines, and threatening, in case he should not obey, to sail to Carthage at once and lay accusation against him. When the envoys were now close at hand, Hannibal sent some of the natives who were to pretend that they were kindly disposed to them and who were instructed to say that the general was not there, but had gone some distance away into parts unknown; and they advised the Romans to depart as quickly as possible, before their presence should be reported, lest in the disorder prevailing because of the absence of the general they should lose their lives. The envoys, accordingly, believed them and set out for Carthage. And when an assembly had been called, some of the Carthaginians counselled maintaining peace with the Romans, but the party attached to Hannibal affirmed that the Saguntines were guilty of wrongdoing, and that the Romans were meddling with what did not concern them. Finally those who urged them to make war won the day.
Meanwhile Hannibal in the course of the siege was conducting vigorous assaults, in which many of his men fell and many more were wounded. One day the Carthaginians succeeded in battering down a portion of the wall, and had been daring enough to enter through the breach, when the Saguntines made a sortie and drove them away. As a result the besieged were strengthened, and the Carthaginians gave way to discouragement. Yet they did not leave the city till they had captured it, though the siege dragged on to the eighth month. Many untoward incidents happened during that time, one of which was the dangerous wounding of Hannibal. The place was taken in the following manner. They brought to bear against the wall an engine much higher than the fortifications, and carrying heavy-armed soldiers, some visible, some concealed. While the Saguntines, thing, were vigorously fighting against the men they saw, believing them to be the only ones, those concealed from view dug through the wall from below and found their way inside. The Saguntines, overwhelmed by the unexpectedness of the event, ran up to the citadel
and held a conference, to see whether by any reasonable concessions they might be saved. But as Hannibal held out no moderate terms and no assistance came to them from the Romans, they begged for a cessation of the assaults, on the plea that they wished to deliberate a little about their present situation. During this respite they gathered together the most highly prized of their treasures and cast them into the flames; then such as were incapable of fighting took their own lives, and those who were in the prime advanced in a body against their opponents, and fighting zealously, were cut down.
On their account the Romans and the Carthaginians went to war; for Hannibal, after adding numerous allies to his force, was hastening toward Italy.
The Romans were at the height of their military power and enjoyed absolute harmony among themselves. Thus, unlike most people, who are led by unalloyed good fortune to audacity, but by strong fear to forbearance, they at this time had a very different experience in these matters. For the greater their successes, the more were they sobered; against their enemies they displayed that daring which is a part of bravery, but toward one another they showed the forbearance which goes hand in hand with good order. 
They used their power for the exercise of safe moderation and their orderliness for the acquirement of true bravery; and they did not allow either their good fortune to develop into arrogance or their forbearance into cowardice. They believed that in the latter case sobriety was ruined by bravery and boldness by fear; whereas with them moderation was rendered more secure by bravery and good fortune surer by good order. It was due to this in particular that they carried through so successfully the wars that came upon them and administered both their own affairs and those of the allies so well.
All who dwelt on the near side of the Alps revolted to join the Carthaginians, not because they preferred the Carthaginians to the Romans as leaders, but because they hated the power that ruled them and welcomed the untried. The Carthaginians had allies against the Romans from every one of the tribes that then existed; but all of them taken together we scarcely Hannibal's equal. He could comprehend matters most clearly and plan out most promptly every project that he concerned, notwithstanding the fact that, as a rule, sureness is the result of deliberation and instability the result of a hasty disposition. He was most resourceful in the suddenest emergency, and most steadfast to the point of utter trustworthiness. Not only did he safely handle the affair of the moment, but he accurately read the future beforehand; he proved himself a most capable counsellor in ordinary events and a most accurate judge of the unusual. By these powers he not only handled the situation immediately confronting him most readily and in the briefest time, but also by calculation anticipated the future afar off and considered it as though it were actually present. 
Consequently he, above all other men, met each occasion with suitable words and acts, because he viewed the expected and the actual in the same light. He was able to manage matters thus for the reason that in addition to his natural capacity he was versed in much Phoenician learning common to his country, and likewise in much Greek learning, and furthermore he understood divination by the inspection of entrails.
In addition to such mental qualities he was also equipped with a physique that had been brought to a state of equal perfection, partly by nature and partly by his manner of life, so that he could carry out easily everything that he undertook. He kept his body agile and at the same time as compact as possible; and he could with safety, therefore, run, or stand his ground, or ride at furious speed. He never burdened himself with overmuch food, nor suffered through lack of it, but took more or less with equal readiness, feeling that either was satisfactory. Hardship made him rugged, and on loss of sleep he grew strong.
Possessing these advantages of mind and body, he managed affairs in general as follows. Since he saw that most men were trustworthy only in what concerned their own interest, he himself dealt with them on this principle and expected the same treatment of them, so that he very often succeeded by deceiving persons and very seldom failed by being the object of a plot. 
He regarded as enemies all who could gain an advantage, whether foreigners or his own countrymen, and did not wait to learn their intentions from their acts, but treated them very harshly, assuming that they were desirous of doing whatever injury they could; he thought it better to be the first to act than the first to suffer, and resolved that others should be in his power rather than he in theirs. 
In short, he paid attention to the real nature of things, rather than to the good things said of them, as often as the two did not happen to coincide. However, he showed excessive honor to any of whom he stood in need; for he considered that most men are slaves to such distinction, and saw that they were willing to encounter danger for the sake of it, even contrary to their own interest. 
For these reasons he often refrained himself from opportunities for gain and other most delightful pleasures, but gave a share ungrudgingly to them. Hence he could get them to be zealous partners in hard work also. Furthermore, he subjected himself not only to the same conditions of living as these men, but also to the same dangers, and was the first to perform every task that he demanded of them. For he believed that thus they in their turn would give him unhesitating and eager support in all his projects, since they saw on his part something more than empty words. Towards the rest he always behaved very haughtily; 
and the whole multitude, in consequence, felt either good-will or fear toward him because of their similar conditions of life in the one case, and because of his haughtiness in the other. Consequently, he was fully able to bring low the lofty, to exalt the humble, and in the briefest time to inspire any whom he pleased, now with hesitation, now with boldness, with hope also and despair, regarding the most important matters.
Now that this is not idle report about him, but truthful tradition, his deeds are proof. He won over many new districts of Spain in a short time, and from there carried the war into Italy through the country of the Gauls, most of whom were not only not in league with him, but actually unknown to him. He was the first of non-Europeans, so far as we know, to cross the Alps with an army, and after that he made a campaign against Rome itself, sundering from it almost all its allies, some by force and others by persuasion. 
This, however, he achieved by himself without the aid of the Carthaginian government. He was not sent forth in the beginning by the magistrates at home, nor did he later obtain any great assistance from them. For although they were to enjoy no slight glory and benefit from his efforts, they wished rather not to appear to be leaving him in the lurch than to coöperate effectively in any enterprise.
Thayer's Note:
the citadel: The word used in the Greek text is ajkrovpolin, acropolis: an innermost fortress. For further details, see the articles Arx and Acropolis in Smith's Dictionary of Greek and Roman Antiquities.