Vedius Pollio, a rich Roman, once invited his friend the emperor Augustus to dinner. The entertainment was interrupted when a slave broke a valuable crystal cup. Trying to impress with his toughness, Vedius ordered the slave boy be thrown to the huge moray eels in his fish pond.

But Augustus was not impressed. In fact, he was outraged at this novel form of cruelty. He ordered Vedius to free the slave boy and told the other slaves to bring all the crystal cups they could find and smash them in their master’s presence. He then told Vedius to fill in the fish pond and get rid of the moray eels.

Most Romans, like Augustus, thought cruelty to slaves was shocking. They understood that slaves could not simply be terrified into being good at their job. Instead, the Romans used various techniques to encourage their slaves to work productively and willingly, from bonuses and long-term inducements, to acts designed to boost morale and generate team spirit. All of these say more than we might imagine about how employers manage people successfully in the modern world.

Above all, the story shows how comfortable the Romans were with leadership and command. They believed that there is a world of difference between having the organisational skills to run a unit and actually being able to lead it. By contrast modern managers are often uncomfortable with being promoted above their staff. I worked in a large corporation for a decade and I had numerous bosses who tried to be my friend. Raising yourself over others sits uneasily with democratic ideals of equality. Today’s managers have to pretend to be one of the team.

The Romans would have scoffed at such weakness. Did Julius Caesar take his legions off-site to get them to buy-in to his invasion of Gaul? Successful leaders had to stand out from the crowd and use their superior skills to inspire, cajole and sometimes force people to do what was necessary. Perhaps we would do well to learn from their blunt honesty.

The Romans thought deeply about slavery. They saw the household as the cornerstone of civilised society. Similarly, the modern corporation is the bedrock of the industrial world, without which no kind of modern lifestyle, with all its material comforts, would be possible.

And just as a household needed slaves, so companies need staff. Permanent employees, like slaves, are far more desirable than outsourcing to outsiders. The Romans thought external contractors could never be relied on like members of the primary social group. They failed to turn up when instructed to, took liberties with their fees and, taking little pride in their work, carried out their tasks shoddily. With slaves, however, who were stakeholders in the system, the Romans could be sure that work would be carried out as they wanted it.

So it was vital that the master took the utmost care over whom he admitted to his household. Buying any old slave risked contaminating the morale of the whole household. The prospective slaveowner tried to ascertain all the facts before committing to buy: whether the slave was likely to try to run away, or loiter about aimlessly, or was a drinker.

The Romans thought clever slaves were troublesome and a threat

The law gave some protection here: your money back if the slave turned out to be a gambler, but not if the slave just turned out to be lazy. The philosopher Seneca records how much notice buyers took over where slaves came from, believing that their origin frequently determined whether they would become good slaves. A Roman would not have considered using a nasty little Briton as a personal servant because of his rough manners and appearance. By contrast, young Egyptian boys were thought to make excellent pets.

Slavedealers were known to conceal the defects of their wares by hiding wounds with make-up or knock knees with fine clothing; modern employers must beware the usual tricks used to smarten up a résumé. Like a slavebuyer, they ask questions and dig beneath the surface, all the time assuming that everything they hear is manipulated in some way.

The Romans thought clever slaves were troublesome and a threat. Better to have the loyalty of slaves promoted above their ability than to risk the betrayal of someone with ambition and talent. And in reality those of us who have worked in large corporations are all too familiar with the phenomenon of office politics propelling the promotion of less talented individuals. Romans also took care to research the morals of their would-be slaves: were they liars or overly ambitious? Far from being an individual matter of personality, such issues were considered a vital factor in whether the slave would benefit the Roman household. Indeed, this is something we could recognise more openly today. From Enron to Tesco, personal failings such as greed and a capacity for deceit have played important roles in corrupting corporate life.

Once he bought them, the Roman master tried to rebuild his slaves’ characters to suit his own needs. He made them forget their old gods and start worshipping at the household shrine instead, ridiculing their former beliefs. He might choose to brand them with his own mark. So, too (if less brutally), the modern manager ‘rebrands’ new recruits by teaching them their company’s mission. They must carry out rituals to publicly proclaim their faith in these new goals, such as attending away days (or off-sites) and taking part in humiliating group activities such as paint-balling or karaoke.

The Romans operated a carrot-and-stick approach to their slaves. The stick side could be casually brutal. The emperor Hadrian, generally regarded as a benign and thoughtful emperor, once used his pen to poke out the eye of a slave who interrupted him when he was writing a letter. One first-century BC inscription from Puteoli near Naples describes a municipal flogging service where, for the price of few loaves of bread, the town council would send out workers to flog the slaves of a master who did not want to do the dirty work himself.

Like the weak manager who hides behind the Human Resources department when there is firing to be done, some Roman masters clearly baulked at the violence intrinsic to their system. But most openly embraced taking the unpleasant acts that being a master entailed, seeing them as a means of advertising their power and virility.

Slaves, like staff, were a substantial investment, and this moderated the harshness of their treatment. Each one cost a lot of money, enough to feed a family of four for two years. Treating them too severely simply damaged the value of your assets and reduced the expected return. The Romans thought that such cruelty might generate a short-term increase in performance, but it would soon wear out the slaves. In fact, if you tried to force them beyond the limits of reasonable service, you would end up making your slaves surly and unmanageable.

Such slaves were thought to be a vexation and a curse. Instead, Seneca urged masters to accept their obligation to treat slaves properly. Forgive them their mistakes, he said, chat with them, be polite to them, and share a meal with them. If masters did that, they could expect slaves to carry out their jobs diligently for many years to come.

The Romans knew that workers, even slaves, need incentives and once trained, slaves would be given enough food to do their jobs well, although no more. Extra clothing could also be given for tasks done well. Masters monitored their slaves’ work closely, and linked such benefits to deserving performance. With wage slaves, it might be money rather than food or clothing that acts as the primary incentive but the principle is the same.

Small perks could make a big difference to morale. Masters sometimes made a point of checking the slaves’ rations personally to show them that they were taking an interest in their welfare. Or they would give them some free time to keep their own chickens and pigs and tend their own kitchen gardens, or go foraging in the woods for berries. Sometimes wine would be given out at festivals, but slaveowners also worried that drinking could make even good slaves behave insolently.

Being a household slave was not all about work. It was accepted that there should be some time for relaxation. This maintained morale which in turn improved work rates: a contented slave was a productive slave. It was known that miserable slaves would hang about aimlessly, trying to shirk the work they’d been allotted. Or they would moan constantly. These slaves, like the office malcontent, had to be weeded out for fear that their negativity would infect the wider group.

Few office wage slaves do not dream of throwing off the yoke and becoming ski-instructors or writers

Even when treated relatively well, slaves naturally longed for freedom. This desire could be turned to great advantage by the master. It was a carrot with which to motivate the slave to work diligently and honestly. Romans would commonly free slaves after a decade or so of good service, particularly those domestic slaves with whom they had good relationships. This desire for freedom was also a stick with which to punish the slave if he disappointed in some way. Hope can help men endure all kinds of suffering; hopelessness can cause them to take desperate measures.

In Gellius’ retelling of the famous Aesop fable of Androcles and the lion, the slave Androcles put up with undeserved floggings every day. It was only after endless abuse that he finally took the tremendous risk of running away. No doubt there are few wage slaves who do not also dream of throwing off the yoke of their mundane existence and becoming ski-instructors, writers, or their own self-employed masters. Modern managers must make their staff feel that they are earning enough, or have the possibility of earning enough, that these dreams are possible, however remote they might be in reality.

The Romans might have been more humane in some respects than we imagine, but they did not hesitate to punish their slaves, and to punish brutally. Floggings, crucifixions, torture by means of the rack and breaking the legs with iron bars would all be carried out in public to maximise the impact on the observers. Or a slave’s children might be sold off, never to be seen again.

When it came to being the undisputed boss, the Romans had a distinct advantage over modern managers. They wanted slaves who were content and hardworking but they were not seeking any emotional engagement with them. From boyhood, they learned to command, issuing commands to their slaves: ‘Bring me my cloak!’, ‘Wash my hands!’, ‘Serve me my breakfast, boy!’

In the egalitarian modern world, this kind of behaviour is more a sign of psychosis than good management. But the Romans would have seen many modern management techniques as simply a way to cloak the reality of being boss behind a veneer of equality. The truth is that both legions and businesses need leadership, and leaders need to know how to command. To be sure, maintaining morale and getting staff to support your decisions are important parts of being a successful leader. But the Roman view of leadership was that of setting a course and taking people to that destination, willingly or otherwise.

The Roman master had no desire to ingratiate himself with his slaves or be popular with them. At a fundamental level, most people saw slaves as possessions – Varro calls them ‘tools that can talk’ – who needed little more consideration than we’d give a fridge. They expected their underlings to help them unquestioningly in their struggle to attain personal success and glory. Modern managers cannot be so uninterested in the inner lives of their staff. But they run the risk of forgetting what the Romans knew so well: that being a leader often means cutting oneself off from those below.

The aspiring manager can, however, take heart from the Roman belief that both leaders and slaves are not born but made. Unlike the Greeks who felt that slaves were naturally servile (as Aristotle argued), the Romans believed that what distinguished slaves and masters was simply a matter of fate and training. Rome successfully assimilated large numbers of freed slaves into its citizen body, and it would have made no sense to deny them the opportunity to rise up in society. We cannot know their exact number but it was enough for Augustus to legislate to restrict how many slaves could be freed. We also have many references to people such as the poet Horace, whose father was an ex-slave and who went on to mix in the highest levels of Roman society. The Romans understood that any individual who had sufficient aptitude and was given the right degree of leadership training could become a satisfactory master.

The successful Roman master understood that slaves were not stupid and would take advantage of opportunities to undermine their master’s authority. Oppression, however, meant that outright rebellion was as rare as labour strikes today. The three big slave rebellions, the last of which was led by Spartacus, all took place between 135-71 BC when slaves were cheap and expendable, thanks to rapid Roman conquests, and so were treated appallingly. Most of the time, it was the small-scale acts of resistance that Roman writers warned against. The surviving ancient manuals on estate management urge the master to guard against slaves gossiping, fiddling the accounts, or pretending to be sick. These all chipped away at the master’s authority, and the manuals make it clear that it is vital to promote the most ambitious slaves to the position of overseer in order to ensure the efficient running of the estate.

For Roman masters, owning slaves was never simply a question of economics. Being followed by a great retinue was a status symbol that made masters feel powerful and important. One prefect of Rome, Pedanius Secundus, had 400 slaves in his household. In the same way that a fine horse reflected well upon its rider, so a well-mannered and deferential slave highlighted the merits of his owner. If there were hundreds of them, then so much greater the glory. So too the modern corporate leader are sometimes tempted to bloat their staff as a means of advertising their own importance to the wider world, whether or not those people are really needed for the task at hand. It is our own form of empire-building.

Owning slaves and employing staff are in a simple sense a million miles apart. A comparison of the two is going to provoke, but similarities do exist. It is an uncomfortable truth that both slaveowners and corporations want to extract the maximum possible value from their human assets, without exhausting them or provoking rebellion or escape. At a deep level, managing others always involves finding solutions to the age-old problems of assessing people from limited information, then incentivising, disciplining and rewarding them, to finally being rid of them. However much we might prefer to disguise the harsher side of wage-slavery behind a rhetoric of friendly teamwork, we could benefit from some straightforward Roman honesty. Everyone knew where they stood then – even if, sometimes, that was in the line for crucifixion.