Detail of Title page of London's Dredful Visitation printed with a motief of skulls, hourglasses, and shovels surrounding the text.

Revealing Data: London’s Deadly Visitation

Circulating Now welcomes guest blogger Kristin Heitman, PhD, who shares her insights on seventeenth century data collection and analysis as part of our Revealing Data series. Dr. Heitman is an independent scholar living in Bethesda, Maryland. She and Professor Vanessa Harding of Birkbeck College, University of London, will convene a symposium on the London Bills of Mortality as part of the 2017–18 program of the Folger Institute in Washington, DC.

London’s Dreadful Visitation,1665-66 is often presented as a Bill of Mortality from the Great Plague, in which an estimated 25 percent of Londoners died. The work is actually a collection of reprints of 52 weekly bills plus an annual summary. Its title page declares it a memento mori—a reminder of the imminence of death—while the introduction, written by the printer E. Cotes, argues that perusing the bills plus a bit of careful thought would show that God did not furiously dole out the wages of sin but mercifully spared the survivors, who then had more time to repent.

Title page of London's Dredful Visitation printed with a motief of skulls, hourglasses, and shovels surrounding the text.
London’s Dreadful Visitation, 16651666
National Library of Medicine #2378023R

It is a peculiar document on many counts. First, apart from the striking title page and brief introduction, Cotes provided only a series of numerical tables. The London Bills of Mortality were neither medical records nor a way to document the deaths of individuals. They were tabulated, parish-by-parish counts of burials as compiled each week by the Company of Parish Clerks, a London guild. The original surveillance program, ordered by the English Crown during the plague of 1519, was executed by London’s merchant-aldermen. While other European cities kept plague rolls—rosters in which designated local physicians recorded each plague victim’s name and social status—London recorded only counts.

Second, the Bills included weekly counts of baptisms, and of mortalities not just of plague but of causes such as old age, childbirth, accidents and suicides, smallpox, and scurvy . The Parish Clerks had conducted comprehensive mortality counts for London’s aldermen since the mid-1550s, with baptisms added by the mid-1560s. Cause of death was determined by the local clerk until that duty passed to parish women appointed and trained as inspectors (“searchers”) of the dead, apparently during the plague of 159223. These regular, comprehensive reports went only to London’s aldermen, although the Crown and Chancellor began to receive next-day copies after a formal request from William Cecil, Chancellor to Elizabeth I. Publication began at the turn of the century, in step with the rising numeracy of London’s population. During the plagues of 159697 and 160102, the City’s printer nailed up official broadsides displaying the week’s parish-by-parish counts of baptisms, plague deaths, and total burials. In 162667, the Parish Clerks began to print their own two-sided weekly handbills with data from the broader program instituted in the 1550s, plus an annual summary bill at Christmas. London’s Dreadful Visitation reproduces 1665’s bills in full.

Why would anyone buy a whole year’s worth of outdated handbills? So many of these bills have survived to the present that historians believe they must have sold quite well. Yet they were ephemera, their information outdated from week to week. Cotes framed her work simply as a spiritual exercise, but the official Bills had already gained new interest with John Graunt’s ground-breaking Natural and Political Observations on the Bills of Mortality,1662. Graunt proposed the basic methods of population-data science using only common experience and the “shop arithmetic” of proportions and the four basic operations. He used counts of both baptisms and mortalities drawn from the Bills—not just for plague, but also for more ordinary causes. A fold-out master table appended to the end of the book allowed readers to follow his detailed analysis, acquire the techniques, and make their own calculations and observations. By the time London’s Dreadful Visitation appeared, the Observations had gone through two sold-out editions and a third was in the works.

Even in 1662, however, the market for such works was already both deep and broad. The plagues of 162526 and 163667 had given rise to “commemorative” broadsides that featured dramatic woodcuts, medical advice, prayers for the sick and the nation, advertisements, and tables of weekly mortality counts for previous plagues. In 1636, London printers began to sell “composite” bills, similar in layout and content but likely for personal use, since they left blank space where one could fill in weekly counts as the epidemic unfolded. Still, London’s Dreadful Visitation differs from commemorative and composite bills as well, for it provides neither medical advice nor prayers nor even advertisements—just the reprints of the year’s official Bills.

Many later assumed that Graunt himself produced London’s Dreadful Visitation, as a sort of companion piece to the Observations. We have no evidence for that belief; yet for those who had mastered Graunt’s methods, Cotes’ reprinted tables could reveal God’s hand not striking suddenly in wrath but methodically weaving a complex tapestry of deaths in which plague formed but a single, dreadful thread.

NLM’s History of Medicine Division’s collection holds copies of London’s Dreadful Visitation and all five editions of Graunt’s Observations.

We hear about data every day. In historical medical collections, data abounds, both quantitative and qualitative. In its format, scope, and biases, data inherently contains more information than its face value. This series, Revealing Data, explores how, by preserving the research data of the past and making it publicly available, the National Library of Medicine (NLM) helps to ensure that generations of researchers can reexamine it, reveal new stories, and make new discoveries. As the NLM becomes the new home of data science at the National Institutes of Health (NIH), Circulating Now explores what researchers from a variety of disciplines are learning from centuries of preserved data, and how their work can help us think about the future preservation and uses of the data we collect today.


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