Plague of Cyprian
The Plague of Cyprian is the name given to a pandemic that afflicted the Roman Empire from about AD 249 to 262. The plague is thought to have caused widespread manpower shortages for food production and the Roman army, severely weakening the empire during the Crisis of the Third Century. Its modern name commemorates St. Cyprian, bishop of Carthage, an early Christian writer who witnessed and described the plague. The agent of the plague is highly speculative due to sparse sourcing, but suspects include smallpox, pandemic influenza and viral hemorrhagic fever (filoviruses) like the Ebola virus.
- "Afterwards there broke out a dreadful plague, and excessive destruction of a hateful disease invaded every house in succession of the trembling populace, carrying off day by day with abrupt attack numberless people, every one from his own house. All were shuddering, fleeing, shunning the contagion, impiously exposing their own friends, as if with the exclusion of the person who was sure to die of the plague, one could exclude death itself also. There lay about the meanwhile, over the whole city, no longer bodies, but the carcasses of many, and, by the contemplation of a lot which in their turn would be theirs, demanded the pity of the passers-by for themselves. No one regarded anything besides his cruel gains. No one trembled at the remembrance of a similar event. No one did to another what he himself wished to experience."
In Carthage the "Decian persecution", unleashed at the onset of the plague, perhaps inadvertently led to the criminalization of Christian oath refusal. Fifty years later, North African convert to Christianity Arnobius defended his new religion from pagan allegations:
- "that a plague was brought upon the earth after the Christian religion came into the world, and after it revealed the mysteries of hidden truth? But pestilences, say my opponents, and droughts, wars, famines, locusts, mice, and hailstones, and other hurtful things, by which the property of men is assailed, the gods bring upon us, incensed as they are by your wrong-doings and by your transgressions." 
Cyprian drew moralizing analogies in his sermons to the Christian community and drew a word picture of the plague's symptoms in his essay De mortalitate ("On the Plague"):
- "This trial, that now the bowels, relaxed into a constant flux, discharge the bodily strength; that a fire originated in the marrow ferments into wounds of the fauces; that the intestines are shaken with a continual vomiting; that the eyes are on fire with the injected blood; that in some cases the feet or some parts of the limbs are taken off by the contagion of diseased putrefaction; that from the weakness arising by the maiming and loss of the body, either the gait is enfeebled, or the hearing is obstructed, or the sight darkened;—is profitable as a proof of faith. What a grandeur of spirit it is to struggle with all the powers of an unshaken mind against so many onsets of devastation and death! what sublimity, to stand erect amid the desolation of the human race, and not to lie prostrate with those who have no hope in God; but rather to rejoice, and to embrace the benefit of the occasion; that in thus bravely showing forth our faith, and by suffering endured, going forward to Christ by the narrow way that Christ trod, we may receive the reward of His life and faith according to His own judgment!" 
Accounts of the plague date from about AD 249 to 262. There was a latter incident from 270 involving the death of Claudius II Gothicus, though it's unknown if this was the same plague or a different outbreak. The Historia Augusta says that "in the consulship of Antiochianus and Orfitus the favour of heaven furthered Claudius' success. For a great multitude, the survivors of the barbarian tribes, who had gathered in Haemimontum were so stricken with famine and pestilence that Claudius now scorned to conquer them further.... during this same period the Scythians attempted to plunder in Crete and Cyprus as well, but everywhere their armies were likewise stricken with pestilence and so were defeated."
The severe devastation to the European population from the two plagues may indicate that the people had no previous exposure or immunity to the plague's cause. Historian William Hardy McNeill asserts that both the earlier Antonine Plague (166–180) and the Plague of Cyprian (251–270) were the first transfers from animal hosts to humanity of two different diseases, one of smallpox and one of measles although not necessarily in that order. D. Ch. Stathakopoulos asserts that both outbreaks were of smallpox.
According to historian Kyle Harper, the symptoms attributed by ancient sources to the Plague of Cyprian better match a viral disease causing a hemorrhagic fever, such as ebola, rather than smallpox. (Conversely, Harper believes that the Antonine Plague was caused by smallpox.)
According to historian Kyle Harper, the period of the plague nearly saw the end of the Roman Empire. He states that between AD 248 and 268, ".. the history of Roman is a confusing tangle of violent failures. The structural integrity of the imperial machine burst apart. The frontier system crumbled. The collapse of legitimacy invited one usurper after another to try for the throne. The empire fragmented and only the dramatic success of later emperors in putting the pieces back together prevented this moment from being the final act of Roman imperial history."
The threat of imminent death from the plague and the unwavering conviction among many of the Christian clergy in the face of it won more converts to the faith.
- Kyle Harper (1 November 2017). "Solving the Mystery of an Ancient Roman Plague". The Atlantic. Retrieved 2 December 2017.
- Kyle Harper (2017). "Chapter 4: The Old Age of the World". The Fate of Rome: Climate, Disease, and the End of an Empire. Princeton University Press. ISBN 978-0691166834.
- Zosimus (1814) [translation originally printed]. The New History, Book 1. (scanned and published online by Roger Pearse). London: Green and Chaplin. pp. 16, 21, 31. Retrieved 2016-04-22.
- The power of plagues by Irwin W. Sherman
- Pontius of Carthage, Life of Cyprian. Transl. Ernest Wallis, c. 1885. Online at Christian Classics Ethereal Library.
- Arnobius, Adversus Gentes 1.3. Translated by Hamilton Bryce and Hugh Campbell, c. 1885. Online at Christian Classics Ethereal Library.
- Cyprian, De Mortalitate. Transl. Ernest Wallis, c. 1885. Online at Christian Classics Ethereal Library.
- AD 270.
- Mount Haemus in the Balkans.
- D. Ch. Stathakopoulos Famine and Pestilence in the late Roman and early Byzantine Empire (2007) 95
- Harper, Kyle "Pandemics and Passages to Late Antiquity: Rethinking the Plague of c. 249-70 described by Cyprian," Journal of Roman Archaeology 28 (2015) 223-60.)
- "Saint Cyprian". Encyclopædia Britannica. 9 May 2013.