Popular culture associates the lives of Roman emperors with luxury, cruelty, and debauchery, sometimes rightfully so. One missing attribute in this list is, surprisingly, that this mighty office was most dangerous for its holder. Of the 69 rulers of the unified Roman Empire, from Augustus (d. 14 CE) to Theodosius (d. 395 CE), 62% suffered violent death. This has been known for a while, if not quantitatively at least qualitatively. What is not known, however, and has never been examined is the time-to-violent-death of Roman emperors. This work adopts the statistical tools of survival data analysis to an unlikely population, Roman emperors, and it examines a particular event in their rule, not unlike the focus of reliability engineering, but instead of their time-to-failure, their time-to-violent-death. We investigate the temporal signature of this seemingly haphazardous stochastic process that is the violent death of a Roman emperor, and we examine whether there is some structure underlying the randomness in this process or not. Nonparametric and parametric results show that: (i) emperors faced a significantly high risk of violent death in the first year of their rule, which is reminiscent of infant mortality in reliability engineering; (ii) their risk of violent death further increased after 12 years, which is reminiscent of wear-out period in reliability engineering; (iii) their failure rate displayed a bathtub-like curve, similar to that of a host of mechanical engineering items and electronic components. Results also showed that the stochastic process underlying the violent deaths of emperors is remarkably well captured by a (mixture) Weibull distribution. We discuss the interpretation and possible reasons for this uncanny result, and we propose a number of fruitful venues for future work to help better understand the deeper etiology of the spectacle of regicide of Roman emperors.
What did a Roman emperor have in common with a gladiator? The latter had better odds of surviving a fight than the former had of avoiding a violent death.
Popular culture traditionally associates the lives of Roman emperors with luxury, cruelty, and debauchery, sometimes rightfully so. One missing attribute in this list is, surprisingly, that this mighty office was most dangerous for its holder, as the statistics will show. Consider the following: of the 69 rulers of the unified Roman Empire, from Augustus (d. 14 CE) to Theodosius (d. 395 CE), 43 emperors suffered violent death, that is 62%, either by assassination, the most common mode of death, suicide, or during combat with a foreign enemy of RomeFootnote 1 (Fig. 1). To put this statistic in context and better appreciate its magnitude, compare it with what is considered nowadays a seriously dangerous activity: Himalaya mountaineering. Climbers that summit above 8000 m in the Himalayas have a risk of death of about 4%, a relatively consistent figure for the past 50 years (Amalberti et al., 2005). Roman emperors had an order of magnitude greater risk of violent death than these intrepid climbers.
he odds of survival for a Roman emperor were roughly equivalent to playing the Russian roulette with a six-chambered revolver, in which the participant places not one but four bullets, spins the cylinder to randomize the outcome, and pulls the trigger with the muzzle against his head.
This sinister comparison conjures the notion of random variable, a central protagonist in our story. That the likelihood of violent death for an emperor was high was well-known, if not quantitatively at least qualitatively as far back as Edward Gibbon’s publication of the first volume of his Decline and Fall of the Roman Empire (1776). In discussing the highly energetic emperor Aurelian (ruled from 270 to 275 CE), nicknamed restitutor orbis, restorer of the world or the unity of the Roman empire in the troubled third century (Watson, 1999), one can almost feel Gibbon’s disappointment when reflecting on the emperor’s murderFootnote 2:
Such was the unhappy condition of the Roman emperors, that, whatever might be their conduct, their fate was commonly the same. A life of pleasure or virtue, of severity or mildness, of indolence or glory, alike led to an untimely grave; and almost every reign is closed by the same disgusting repetition of treason and murder [emphasis added].
He then added, “the Roman senators heard, without surprise, that another emperor had been assassinated in his camp”.
It is worth taking a little historical detour at this point, back to the time before this track record of treason and murder Gibbon refers to was even started, to revisit a popular landmark quotation and understand it in a new light, Julius Caesar’s “Iacta alea est”…
Go to RL to read a MUCH more in depth discussion of this statistic[//i]