Helen Cam (1885-1968), the first woman to be elected to a chair at Harvard, was a formidable English medievalist. Unusually for a legal historian, she had a keen eye for the human dramas not entirely concealed behind the formulae of legal records – for instance, in Year Book reports.

This characteristic echoes her little-known interest in historical novels, evidenced by her Historical Association pamphlet of that title (1961). It offers a reflective survey of the genre, based on a redoubtable breadth of reading, predominantly Anglocentric: that she thinks Alessandro Manzoni’s The Betrothed (1827 and 1842) is set during Napoleon’s Italian campaign demonstrates that she can never have read it. The pamphlet concludes with a list of over 200 titles, categorised by period and divided into three classes in terms of quality: A, B or C – with a very few A*. The classifications reveal Cam’s uncompromising confidence in her own judgement. Giuseppe Tomasi di Lampedusa’s then new The Leopard (1958) is given an A, though without the stars awarded to Sigrid Undset’s Kristin Lavransdatter (a trilogy, published in Norwegian 1920-22), H.F.M. Prescott’s The Man on a Donkey (1952) and Leo Tolstoy’s War and Peace (1869). Charles Dickens’ A Tale of Two Cities (1859) is dismissed with a stingy B+ and Barnaby Rudge (1841), his other historical novel, is not even mentioned.

The genre can easily be dismissed by the historically high-minded as necessarily straying beyond the surviving evidence to invent what might have happened, been said, and been thought and felt, rather than what is still recorded. No historian was more high-minded than Cam, but this was not her view. She thought that provided sufficient care were taken to ensure that not only the facts but also the attitudes and assumptions displayed by characters were in accordance with what was known about the context, then a novel could be both fulfilling as literature, and historically illuminating.

This is true not only for children – inspiring novels intended for them are identified in the list by a J (for ‘juveniles’) – but for any reader. The novelist can recreate features of a long dead society through the eyes of particular individuals, whether real or fictional; and also the mental world of such characters, in a way that sticking solely to evidence largely precludes. Provided that such reconstructions are compatible with the evidence, they can deepen historical understanding in ways not available to the historian. Because the perspectives are those of individuals, they are partial: an instance not given by Cam is Robert Browning’s verse novel The Ring and the Book (1869), which provides nine different accounts of a multiple murder committed in Rome in 1698. It was inspired by a manuscript of depositions in the ensuing court case which Browning found in a market in Florence in 1860. Avowedly based on this evidence, Browning greatly elaborates it.

In doing so, he was engaging in imaginative historical reconstruction, much as historians must do – when, in the words of the great legal historian S.F.C. Milsom, they have to work out the most plausible lines to draw between the few surviving dots of evidence. Many pictures are possible, but which is the most probable? Milsom made up overtly hypothetical individuals to illustrate the predicaments in which he imagined litigants might find themselves. But in his case, there was no novelist’s pretence that the motives he reconstructed were those of rounded characters. He was interested in legal motives, determined by procedural logic; the fictional names on which they were foisted were no more than mannikins. His sources offered almost no clues to the wider concerns of real individuals. It was Milsom who told me about the delight Cam took in the dramas behind Year Book reports, in which more individual detail is often recorded. In her view, an historical novelist was licensed to go far further beyond the evidence than an historian legitimately could. She does not say so, but the type of imagination involved is nevertheless much the same.

When evidence is very restricted, and – as in the medieval period, on which Cam and Milsom concentrated – reveals almost nothing about most aspects of most lives, then recovering individual thought and feeling is predominantly a matter of highly disciplined imaginative inference. This is true even of a quite exceptionally well-evidenced medieval life, illuminated in R.W. Southern’s masterpiece, Anselm: A Portrait in a Landscape (1990). This example establishes that it is not writing from an individual viewpoint which distinguishes an historical novel from a work of history, as Cam asserts, but the extent to which an author in doing so is ready to create by inference, and the literary form of such creativity.

It is the dearth of evidence that means that it is still more difficult to pull off a successful novel set in the Middle Ages than in the early modern period: compare, for instance, Walter Scott’s Ivanhoe (1819) with his Old Mortality (1816). In early modern and subsequent periods we know so much more about how a far wider range of people, including laymen, thought; and how they expressed themselves in a recognisable vernacular. Early modern dialogue can ring true in a way that medieval cannot; through contemporary drama, we are steeped in examples of it.

Other sorts of writing, too, give a much better sense of the mental world of individuals. One may remain unconvinced by Hilary Mantel’s highly sympathetic imagining, in her Wolf Hall trilogy (2009-20), of Thomas Cromwell’s inner life; but the period means that it was possible for her to frame it in a way that does not jar. Jesse Norman’s The Winding Stair (2023), the story of the lifelong rivalry between Francis Bacon and Edward Coke, offers plausible constructions of their private thoughts, and verisimilar conversation. It is suggestive in a way that a dual biography could not legitimately be.

As readers reflect on their summer reading, perhaps History Today might encourage them to submit Cam-style classifications of historical novels.

George Garnett is Professor of Medieval History at Oxford University, Fellow of St Hugh’s College and the author of The Norman Conquest in English History: Volume I: A Broken Chain? (Oxford University Press, 2021).