How Roman Emperors Handled The Succession Problem


A relief from Trajan’s Column

[Crossposted from my Medium blog]

Institutions built by one generation of founders must be successfully handed off to the next to keep them functional. In the absence of such succession, organizational sclerosis or constant internal conflict sets in.

The succession problem has two components: skill succession and power succession. In public discourse and political thought we have tried to solve either power succession or skill succession under different names. We seamlessly switch between two separate fragmented states of mind depending on which facet of the problem is in front of us without even noticing.

Our culture is pervaded with an ideology of proving worth through struggle. This almost Darwinian view is strongly present in our economic, political, and even academic values. We define merit by equating it with success in competition, not even realizing this was merely one of many possible choices.

These values then underwrite various legal and social barriers and obstacles imposed on power succession, that are widely believed to solve skill succession.

When it comes to our private decisions, we are of a more nepotistic mindset. We can in it more cleanly think about power succession. In this mode we usually fudge skill evaluation, however.

What is missing from Western understanding is that power succession and skills succession are not actually at odds with each other, as our meritocratic ideology would have you believe, but are actually two mutually necessary halves. If your goal is to keep institutions functional, solutions that solve one but not the other are not solutions at all.

The example of Roman adoption is used to explore and illustrate this. The Roman Empire is one of the greatest civilizations of all time. In this piece, we examine its surprising solution to the succession problem, the practice of adult adoption, for insight into what kind of social norms and institutional features would be necessary in a modern solution.

When in Rome...

Roman society is correctly noted for its production of highly skilled individuals. The society had no problem with skill succession - ambitious and greatly talented individuals abounded. They found a challenge in power succession, however. The early Republic was anomalous and impressive in how cooperative the elites were (among themselves at least).

Cincinnatus could be called upon by the senate to be dictator in an emergency, then earn the admiration of his peers by choosing to seamlessly retire back to his farm after the crisis passed, without fear of reprisals from former political rivals. They trusted that his retirement was genuine and that he would no longer be a towering figure in politics.

Contrast this with modern Libya. Muammar Gaddafi’s gruesome death at the hands of the National Transition Council militia is infamous. Even absent American and French interventions that toppled him, if he had handed power over to his political opposition, a peaceful retirement seems unlikely at best.

The Roman republican system eventually met its limits as it grew from managing a provincial Rome and its client states on the Italian Peninsula to managing a more complex urban economy and the political life of the entire Western Mediterranean.

Problems that could previously be solved by aligned political fundamentals or the social fabric of the patrician class grew difficult. They fell more and more on the formal religious and legal structures of the republic.

These structures, once the last recourse, could not bear the burden of regular use. What were once dire contingencies resorted to once the failure of coordination became apparent, came to be seen as normal political moves. Roman economic, military and political elites grew steadily less cooperative.

By the late republic, talented people still arose but were forced to fight bloody civil wars to resolve disputes. The career of Sulla for example is littered with political opponents defeated not just on the senate floor but on the field of battle.

Long after these civil wars changed the Roman state beyond recognition, Roman Emperors found an inventive solution for the newly apparent problem of power succession. In subsequent periods of stability, such as during the Nerva-Antonine dynasty, this was achieved with the use of adoption.

In Roman society adoption wasn’t solely a means to help orphaned or abandoned children, but a social and legal mechanism with which you could make an adult your son and heir, allowing him to inherit your position. In other words, your dynasty didn’t need to end with your bloodline.

This solution has many interesting features, the most notable of which is that the emperor can work out an agreement with a rising younger rival. Adoption legibly positions them as the natural successor.

Since the practice of adult adoption was well understood and respected throughout Roman society, it amounted to a credible guarantee. Credible guarantees changed incentives notably.

The adopted son, who might have previously been tempted to undermine the emperor, should now be in favor of expanding a power base that will one day be his. The current and future rulers, then, have reason to work together even before the transfer of power is affected. The result is not only a peaceful transfer of power, but a political alchemy that transmutes your most dangerous rival into your most potent ally.

A well-respected law backed by legal practice is what ensures that wealth and other legal rights are properly transferred. Importantly, the legitimacy of the social practice of adoption, together with the expectation of future power, meant that intangible social connections, so vital to securing power, are transferred as well.

Even if the chosen successor and head of state are not in the closest political allegiance due to other factors, this adoption mechanism can still be used to formalize the capacity to carry out a coup to put that person in charge, or at least in the waiting line for formal governance, without a civil war. This solves one of the greatest difficulties with negotiated surrenders and peace negotiations in general, that of credible commitment.

The mechanism has benefits in terms of skill succession as well, since it allows a skilled pilot, in this case a skilled ruler, to recognize and pick another with comparable skill. This turned out to be the case, as the era of the Nerva-Antonine dynasty saw relatively peaceful and competent governance.

The term “Five Good Emperors” has been used to refer to a chain of five good rulers from the Nerva-Antonine dynasty (Nerva,<a href=""> Trajan,<a href=""> Hadrian,<a href=""> Antoninus Pius and<a href=""> Marcus Aurelius). The famous British historian Edward Gibbon went so far in his praise as to say mankind never had as happy a condition before or after as under their rule.

The relative harmony of this period provides an important contrast with the civil wars seen earlier in the late republic and later in imperial history. Adoption proved a viable method of solving power succession.

The more complex the solution, the more fragile it is

The most developed version of the system of adoptive succession was implemented centuries later under Diocletian. The practice of adoption was less prominent in Roman society by that point, so the stability of the guarantee was more questionable, since it was no longer a celebrated cultural practice. Diocletian revived it for use as a legal succession mechanism and developed it further by implementing a system of seniority and apprenticeship. The appointed successor was granted the title of Caesar (junior Emperor) and would be allowed to manage their own lands, under nominal supervision of the Augustus (senior Emperor).

This sweetens the deal; not only will I name you my son and by culture and law make you inheritor, I will grant or acknowledge your right to manage territories right now.

An advantage of this approach is that the senior position is directly analogous in terms of skills and responsibilities required to the junior one. The job of head of state is usually sufficiently unique that preparation, training, and directly relevant experience are infamously hard to come by. A disadvantage is that it favors the junior party, perhaps to the point of making premature conflict a viable route to power.

The Roman Empire was experiencing great difficulties in this era, having become sclerotic and bureaucratized. Military and administrative demands made the division of the Empire into a Western and Eastern half politically advantageous. In the landscape of power, high was then composed of a four-way alliance, a tetrarchy of the Eastern and Western senior emperors, and their junior successors.

This more complicated arrangement proved more unstable than the Nerva-Antonine dynasty. The balance of power between four skilled individuals is a hard thing to maintain. Every now and then there do arise cooperative strategists that can make such a balance of power work, but the skill requirement for the job rises. The tetrarchy was stable only under Diocletian himself. He managed the feat of safely retiring. Unfortunately in his old age he also lived to see the system fall.

More complicated systems of succession and coordination are generally fragile, since in those cases successful power succession relies on successful skill succession. The more robust approach is to aim for skill succession, but enable power succession in its absence or partial success.

There are examples of seemingly very complex systems of succession that have endured for centuries. An example of complicated constitutional arrangements was the Republic of Venice, the longest lived republic. Such arrangements are however best thought of as very complicated legal machinery that validate and render legal any decision arrived through some other means (the selection of the Doge of Venice was likely accomplished by direct negotiation between the patrician families of Venice, not through the nominal selection procedure).


Successfully transferring not only the formal, but also informal, position that allows an individual to shape an organization is necessary for keeping an institution functional. On the scale of societies, employing solutions that prevent destructive conflicts between elites is vital.

Adoption of adults was a viable solution in the Roman Empire for as long as the social fabric underwriting it was there. As the underlying social norms changed, the legal norms that made it possible required backing by more complicated mechanisms and workarounds. This architecture proved less successful, in part because its complexity made it more difficult to maintain.

We cannot simply copy the Roman solution because our own social and legal norms are different. While adult adoption is legal in many Western countries, the Roman social practice would be considered an exploit, and would leave the companies and organizations that used it open to attack. The challenge, then, is finding a solution that would work as well and is as simple as possible.

It is important to note that in modern Japan, a technologically developed industrial economy, we actually observe a similar practice. It is termed Mukoyōshi, where a son-in-law is chosen primarily for the ability to run the family business. They marry into the family and take on the family name. The practice can be found in the history of companies such as Suzuki, Kikkoman, and Toyota.

It might be tempting to try to imitate Mukoyōshi in the Western context. The legal vehicle of marriage certainly seems more appropriate for the task than our adoption laws. The crucial problem, however, lies in how we choose marriage partners in the West. Our choice of spouse is a personal and romantic, rather than a business and family matter. This means that while we could use marriage for power succession, its appropriateness for solving the problem of skill succession is dubious.

Despite the obstacles to its direct application, the Roman solution displays features we can and should emulate in our own institutional thinking. When pursuing reform, setting cultural expectations, or building new organizations with the intent to solve the succession problem, we should aim for simplicity of mechanism (robustness), have the mechanism carry over informal as well as formal resources, and ensure that the incentives of the successor and the current pilot are as aligned as possible.