Almighty God uses thunder, lightning and other blows which issue from his throne to scourge the sons whom he wishes to redeem. Accordingly, since a catastrophic pestilence from the East has arrived in a neighbouring kingdom, it is very much to be feared that, unless we pray devoutly and incessantly, a similar pestilence will stretch its poisonous branches into this realm, and strike down and consume the inhabitants.
Thus Bishop Ralph of Shrewsbury wrote to the archdeacons of his diocese on 17 August, 1348.
Unfortunately, the prayers and the processions that he ordered failed to prevent the Black Death crossing the Channel from France. A year later the Prior of Canterbury asked the bishops in the southern province to take action:
“Terrible is God towards the sons of men, and by his command all things are subdued to the rule of his will. Those whom he loves he censures and chastises; that is, he punishes their shameful deeds in various ways during this mortal life so that they might not be condemned eternally. He often allows plagues, miserable famines, conflicts, wars and other forms of suffering to arise, and uses them to terrify and torment men and so drive out their sins.”
The populations suffering the devastating pandemics of the fourteenth century were at once powerless and active agents in their own destiny. All were exposed to the wrath of a vengeful God, but through prayers, penitential processions and reformed morals it might be possible to hasten the end of a plague and delay its recurrence.
Over the succeeding centuries, the practical task of managing populations and devising cures in a pandemic has gradually transferred to governments and scientists. The moral drama of sin, retribution and repentance, has, however, continued in a new form.
Successive outbreaks of respiratory diseases in this century have been blamed on man’s increasing exposure to infected wildlife. SARS (Severe Acute Respiratory Syndrome) in 2003, MERS (Middle East Respiratory Syndrome) in 2012, and now Covid-19 have crossed the species barrier, probably from bats which carry a wide range of pathogens. An increasing body of literature, together with organizations such as the Coalition for Epidemic Preparedness Innovations, have warned that, like the Black Death in the fourteenth century, one pandemic is almost certain to be followed by another in a matter of years.
Animals may be the proximate cause, but the fundamental problem is the behaviour of people. Land is cleared for population growth, the exploitation of raw materials, and for dairy and meat farming, and as a consequence there are lethal encounters with hitherto isolated reservoirs of viruses. The risks are compounded by the rapid increase in international travel and commerce. The pandemics thus become a metonym for the ecological crisis more generally. As the Professor of the History of Medicine at Oxford writes, “‘emerging diseases’, as they are often termed, have been seen as Nature’s retribution for environmental degradation.” 
Mankind has misbehaved, is being punished, and, with increasing urgency, is seeking effective forms of repentance.
The Christian churches, pushed to the side-lines by the secular response to disease, are seeking to reclaim the leadership of what they see as a new moral crusade. “I think the future we are called to build”, writes Pope Francis in response to Covid-19, “has to begin with an integral ecology, an ecology that takes seriously the cultural and ethical deterioration that goes hand in hand with our ecological crisis.” The Archbishop of Canterbury wrote in 1375 that, “in our modern times, alas, we are mired in monstrous sin and the lack of devotion among the people provokes the anger of the great king to whom we should devote our prayers. As a result we are assailed by plagues or epidemics”. In a pale echo, we have the words of the 105th incumbent: “Around the world, climate change is affecting food security, creating social vulnerability, and disrupting peace and security. There is no doubt we need to act.”
This time, praying will not be enough.
 Register of Bishop Ralph of Shrewsbury, Somerset Record Society X (1896), 555-6, cited in Rosemary Horrox, trans. and ed., The Black Death (Manchester: Manchester University Press, 1994), p. 112. Despite his title, Ralph, formerly Chancellor of the University of Oxford, was Bishop of Bath and Wells, where he was described by the Dictionary of National Biography as “a wise and industrious bishop, learned and extremely liberal.”
 D. Wilkins, Concilia Magnae Britanniae et Hiberniae (1739), vol. II, p. 738, cited in Horrox, Black Death, p. 113.
 Mark Harrison, Disease and the Modern World. 1500 to the Present Day (Cambridge: Polity, 2004), p. 189. See also, Mark Honigsbaum, The Pandemic Century. A History of Global Contagion from the Spanish Flu to Covid-19 (Penguin: London, 2020), pp. xiv-xv, 280.
 Pope Francis, in conversation with Austen Ivereigh, Let Us Dream. The Path to a Better Future (London: Simon and Schuster, 2020), p. 35.
 Wilkins, Concilia, III, pp. 100-1, cited in cited in Horrox, Black Death, p. 120