Sallust was a Roman senator and contemporary of Caesar and of Cicero (late first century BC).  He was born into a well to do, though not aristocratic, Italian family residing some 100 miles north of Rome.  He was wealthy enough to afford a political career in the capital and advanced though lower offices as political dependent of Julius Caesar eventually reaching the rank of praetor (just below that of consul).  For reasons that are not entirely clear, he was expelled from the Roman Senate went into retirement and began to write history.  The passage here is the introduction to a monograph on a failed coup d'etat of the year 61.  In its Sallust gives his views on human nature and the dynamics of Roman success and failure as a constitutional system. 

1. It becomes all men, who desire to excel other animals, to strive, to the utmost of their power, not to pass through life in obscurity, like the beasts of the field, which nature has formed grovelling and subservient to appetite. All our power is situate in the mind and in the body. Of the mind we rather employ the government; of the body, the service. The one is common to us with the gods; the other with the brutes. It appears to me, therefore, more reasonable to pursue glory by means of the intellect than of bodily strength, and, since the life which we enjoy is short, to make the remembrance of us as lasting as possible. For the glory of wealth and beauty is fleeting and perishable; that of intellectual power is illustrious and immortal. Yet it was long a subject of dispute among mankind, whether military efforts were more advanced by strength of body, or by force of intellect. For, in affairs of war, it is necessary to plan before beginning to act, and, after planning, to act with promptitude and vigour. Thus, each being insufficient of itself, the one requires the assistance of the other.
2. In early times, accordingly, kings (for that was the first title of sovereignty in the world) applied themselves in different ways- some exercised the mind, others the body. At that period, however, the life of man was passed without covetousness; every one was satisfied with his own. But after Cyrus in Asia, and the Lacedaemonians and Athenians in Greece, began to subjugate cities and nations, to deem the lust of dominion a reason for war, and to imagine the greatest glory to be in the most extensive empire, it was then at length discovered, by proof and experience, that mental power has the greatest effect in military operations. And, indeed, if the intellectual ability of kings and magistrates were exerted to the same degree in peace as in war, human affairs would be more orderly and settled, and you would not see governments shifted from hand to hand, and things universally changed and confused. For dominion is easily secured by those qualities by which it was at first obtained. But when sloth has introduced itself in the place of industry, and covetousness and pride in that of moderation and equity, the fortune of a state is altered together with its morals; and thus authority is always transferred from the less to the more deserving. Even in agriculture, in navigation, and in architecture, whatever man performs owns the dominion of intellect. Yet many human beings, resigned to sensuality and indolence, uninstructed and unimproved, have passed through life like travellers in a strange country; to whom, certainly, contrary to the intention of nature, the body was a gratification, and the mind a burden. Of these I hold the life and death in equal estimations, for silence is maintained concerning both. But he only, indeed, seems to me to live, and to enjoy life, who, intent upon some employment, seeks reputation from some ennobling enterprise, or honourable pursuit. But in the great abundance of occupations, nature points out different paths to different individuals.
3. To act well for the Commonwealth is noble, and even to speak well for it is not without merits. Both in peace and in war it is possible to obtain celebrity; many who have acted, and many who have recorded the actions of others, receive their tribute of praise. And to me, assuredly, though by no means equal glory attends the narrator and the performer of illustrious deeds, it yet seems in the highest degree difficult to write the history of great transactions; first, because deeds must be adequately represented by words; and next, because most readers consider that whatever errors you mention with censure, are mentioned through malevolence and envy; while, when you speak of the great virtue and glory of eminent men, every one hears with acquiescence only that which he himself thinks easy to be performed; all beyond his own conception he regards as fictitious and incredible. I myself, however, when a young man, was at first led by inclination, like most others, to engage in political affairs; but in that pursuit many circumstances were unfavourable to me; for, instead of modesty, temperance, and integrity, there prevailed shamelessness, corruption, and rapacity. And although my mind, inexperienced in dishonest practice, detested these vices, yet, in the midst of so great corruption, my tender age was ensnared and infected by ambition; and though I shrunk from the vicious principles of those around me, yet the same eagerness for honours, the same obloquy and jealousy, which disquieted others, disquieted myself.
4. When, therefore, my mind had rest from its numerous troubles and trials, and I had determined to pass the remainder of my days unconnected with public life, it was not my intention to waste my valuable leisure in indolence and inactivity, or, engaging in servile occupations, to spend my time in agriculture or hunting; but, returning to those studies from which, at their commencement, a corrupt ambition had allured me, I determined to write, in detached portions, the transactions of the Roman people, as any occurrence should seem worthy of mention; an undertaking to which I was the rather inclined, as my mind was uninfluenced by hope, fear, or political partisanship. I shall accordingly give a brief account with as much truth as I can, of the Conspiracy of Catiline; for I think it an enterprise eminently deserving of record, from the unusual nature both of its guilt and of its perils. But before I enter upon my narrative, I must give a short description of the character of the man.
5. Lucius Catiline was a man of noble birth, and of eminent mental and personal endowments, but of a vicious and depraved disposition. His delight, from his youth, had been in civil commotions, bloodshed, robbery, and sedition; and in such scenes he had spent his early years. His constitution could endure hunger, want of sleep, and cold, to a degree surpassing belief. His mind was daring, subtle, and versatile, capable of pretending or dissembling whatever he wished. He was covetous of other men's property, and prodigal of his own. He had abundance of eloquence, though but little wisdom. His insatiable ambition was always pursuing objects extravagant, romantic, and unattainable. Since the time of Sulla's dictatorship, a strong desire of seizing the government possessed him, nor did he at all care, provided that he secured power for himself, by what means he might arrive at it. His violent spirit was daily more and more hurried on by the diminution of his patrimony, and by his consciousness of guilt; both which evils he had increased by those practices which I have mentioned above. The corrupt morals of the state, too, which extravagance and selfishness, pernicious and contending vices, rendered thoroughly depraved, furnished him with additional incentives to action. Since the occasion has thus brought public morals under my notice, the subject itself seems to call upon me to look back, and briefly to describe the conduct of our ancestors in peace and war; how they managed the state, and how powerful they left it; and how, by gradual alteration, it became, from being the most virtuous, the most vicious and depraved.
6. Of the city of Rome, as I understand, the founders and earliest inhabitants were the Trojans, who, under the conduct of Aeneas, were wandering about as exiles from their country, without any settled abode; and with these were joined the Aborigines, a savage race of men, without laws or government, free and owning no control. How easily these two tribes, though of different origin, dissimilar language, and opposite habits of life, formed a union when they met within the same walls, is almost incredible. But when their state, from an accession of population and territory, and an improved condition of morals, showed itself tolerably flourishing and powerful, envy, as is generally the case m human affairs, was the consequence of its prosperity. The neighbouring kings and people, accordingly, began to assail them in war, while a few only of their friends came to their support; for the rest, struck with alarm, shrunk from sharing their dangers. But the Romans, active at home and in the field, prepared with alacrity for their defence. They encouraged one another, and hurried to meet the enemy. They protected with their arms, their liberty, their country, and their homes. And when they had at length repelled danger by valour, they lent assistance to their allies and supporters, and procured friendships rather by bestowing favours than by receiving them. They had a government regulated by laws. The denomination of their government was monarchy. Chosen men, whose bodies might be enfeebled by years, but whose minds were vigorous in understanding, formed the council of the state; and these, whether from their age, or from the similarity of their duty, were called fathers . But afterwards, when the monarchical power, which had been originally established for the protection of liberty, and for the promotion of the public interest, had degenerated into tyranny and oppression, they changed their plan, and appointed two magistrates, with power only annual; for they conceived that, by this method, the human mind would be least likely to grow overbearing through want of control.
7. At this period every citizen began to seek distinction, and to display his talents with greater freedom; for, with princes, the meritorious are greater objects of suspicion than the undeserving, and to them the worth of others is a source of alarm. But when liberty was secured, it is almost incredible how much the state strengthened itself in a short space of time, so strong a passion for distinction had pervaded it. Now, for the first time, the youth, as soon as they were able to bear the toils of war, acquired military skill by actual service in the camp, and took pleasure rather in splendid arms and military steeds than in the society of mistresses and convivial indulgence. To such men no toil was unusual, no place was difficult or inaccessible, no armed enemy was formidable; their valour had overcome everything. But among themselves the grand rivalry was for glory; each sought to be first to wound an enemy, to scale a wall, and to be noticed while performing such an exploit. Distinction such as this they regarded as wealth, honour, and true nobility. They were covetous of praise, but liberal of money; they desired competent riches, but boundless glory. I could mention, but that the account would draw me too far from my subject, places in which the Roman people, with a small body of men, routed vast armies of the enemy; and cities which, though fortified by nature, they carried by assault.
8. But, assuredly, Fortune rules in all things. She makes everything famous or obscure rather from caprice than in conformity with truth. The exploits of the Athenians, as far as I can judge, were very great and glorious, yet something inferior to what fame has represented them. But because writers of great talent flourished there, the actions of the Athenians are celebrated over the world as the most splendid of achievements. Thus, the merit of those who have acted is estimated at the highest point to which illustrious intellects could exalt it in their writings. But among the Romans there was never any such abundance of writers; for, with them, the most able men were the most actively employed. No one exercised the mind independently of the body; every man of ability chose to act rather than narrate, and was more desirous that his own merits should be celebrated by others, than that he himself should record theirs.
9. Good morals, accordingly, were cultivated in the city and in the camp. There was the greatest possible concord, and the least possible avarice. Justice and probity prevailed among the citizens, not more from the influence of the laws than from natural inclination. They displayed animosity, enmity, and resentment only against the enemy. Citizens contended with citizens in nothing but honour. They were magnificent in their religious services, frugal in their families, and steady in their friendships. By these two virtues, intrepidity in war, and equity in peace, they maintained themselves and their state. Of their exercise of which virtues, I consider these as the greatest proofs; that, in war, punishment was oftener inflicted on those who attacked an enemy contrary to orders, and who, when commanded to retreat, retired too slowly from the contest, than on those who had dared to desert their standards or, when pressed by the enemy, to abandon their posts; and that, in peace, they governed more by conferring benefits than by exciting terror, and, when they received an injury, chose rather to pardon than to revenge it.
10. But when, by perseverance and integrity, the republic had increased its power; when mighty princes had been vanquished in war; when barbarous tribes and populous states had been reduced to subjection; when Carthage, the rival of Rome's dominion, had been utterly destroyed, and sea and land lay everywhere open to her sway, Fortune then began to exercise her tyranny, and to introduce universal innovation. To those who had easily endured toils, dangers, and doubtful and difficult circumstances, ease and wealth, the objects of desire to others, became a burden and a trouble. At first the love of money, and then that of power, began to prevail, and these became, as it were, the sources of every evil. For avarice subverted honesty, integrity, and other honourable principles, and, in their stead, inculcated pride, inhumanity, contempt of religion, and general venality. Ambition prompted many to become deceitful; to keep one thing concealed in the breast, and another ready on the tongue; to estimate friendships and enmities, not by their worth, but according to interest; and to carry rather a specious countenance than an honest heart. These vices at first advanced but slowly, and were sometimes restrained by correction; but afterwards, when their infection had spread like a pestilence, the state was entirely changed, and the government, from being the most equitable and praiseworthy, became rapacious and insupportable.
11. At first, however, it was ambition, rather than avarice, that influenced the minds of men; a vice which approaches nearer to virtue than the other. For of glory, honour, and power, the worthy is as desirous as the worthless; but the one pursues them by just methods; the other, being destitute of honourable qualities, works with fraud and deceit. But avarice has merely money for its object, which no wise man has ever immoderately desired. It is a vice which, as if imbued with deadly poison, enervates whatever is manly in body or mind. It is always unbounded and insatiable, and is abated neither by abundance nor by want. But after Lucius Sulla, having recovered the government by force of arms, proceeded, after a fair commencement, to a pernicious termination, all became robbers and plunderers; some set their affections on houses, others on lands; his victorious troops knew neither restraint nor moderation, but inflicted on the citizens disgraceful and inhuman outrages. Their rapacity was increased by the circumstance that Sulla, in order to secure the attachment of the forces which he had commanded in Asia, had treated them, contrary to the practice of our ancestors, with extraordinary indulgence, and exemption from discipline; and pleasant and luxurious quarters had easily, during seasons of idleness, enervated the minds of the soldiery. Then the armies of the Roman people first became habituated to licentiousness and intemperance, and began to admire statues, pictures, and sculptured vases; to seize such objects alike in public edifices and private dwellings; to spoil temples; and to cast off respect for everything, sacred and profane. Such troops, accordingly, when once they obtained the mastery, left nothing to the vanquished. Success unsettles the principles even of the wise, and scarcely would those of debauched habits use victory with moderation.
12. When wealth was once considered an honour, and glory, authority, and power attended on it, virtue lost her influence, poverty was thought a disgrace, and a life of innocence was regarded as a life of ill-nature. From the influence of riches, accordingly, luxury, avarice, and pride prevailed among the youth; they grew at once rapacious and prodigal; they undervalued what was their own, and coveted what was another's; they set at nought modesty and continence; they lost all distinction between sacred and profane, and threw off all consideration and self-restraint. It furnishes much matter for reflection, after viewing our modern mansions and villas extended to the size of cities, to contemplate the temples which our ancestors, a most devout race of men, erected to the Gods. But our forefathers adorned the fanes of the deities with devotion, and their homes with their own glory, and took nothing from those whom they conquered but the power of doing harm; their descendants, on the contrary, the basest of mankind have even wrested from their allies, with the most flagrant injustice, whatever their brave and victorious ancestors had left to their vanquished enemies; as if the only use of power were to inflict injury.
13. For why should I mention those displays of extravagance, which can be believed by none but those who have seen them; as that mountains have been levelled, and seas covered with edifices, by many private citizens; men whom I consider to have made a sport of their wealth, since they were impatient to squander disreputably what they might have enjoyed with honour. But the love of irregular gratification, open debauchery, and all kinds of luxury, had spread abroad with no less force. Men forgot their sex; women threw off all the restraints of modesty. To gratify appetite, they sought for every kind of production by land and by sea; they slept before there vas any inclination for sleep; they no longer waited to feel hunger, thirst, cold, or fatigue, but anticipated them all by luxurious indulgence. Such propensities drove the youth, when their patrimonies were exhausted, to criminal practices; for their minds, impregnated with evil habits, could not easily abstain from gratifying their passions, and were thus the more inordinately devoted in every way to rapacity and extravagance.
14. In so populous and so corrupt a city, Catiline, as it was very easy to do, kept about him, like a body-guard, crowds of the unprincipled and desperate. For all those shameless, libertine, and profligate characters, who had dissipated their patrimonies by gaming, luxury, and sensuality; all who had contracted heavy debts, to purchase immunity for their crimes or offences; all assassins or sacrilegious persons from every quarter, convicted or dreading conviction for their evil deeds; all, besides, whom their tongue or their hand maintained by perjury or civil bloodshed; all, in fine, whom wickedness, poverty, or a guilty conscience disquieted, were the associates and intimate friends of Catiline. And if any one, as yet of unblemished character, fell into his society, he was presently rendered, by daily intercourse and temptation, similar and equal to the rest. But it was the young whose acquaintance he chiefly courted; as their minds, ductile and unsettled from their age, were easily ensnared by his stratagems. For as the passions of each, according to his years, appeared excited, he furnished mistresses to some, bought horses and dogs for others, and spared, in a word, neither his purse nor his character, if he could but make them his devoted and trustworthy supporters. There were some, I know, who thought that the youth, who frequented the house of Catiline, were guilty of crimes against nature; but this report arose rather from other causes than from any evidence of the fact.