Trevor-Roper's commentary on this passage is to be found on a single sheet amongst his papers headed "Gibbon's deism". Before quoting from the conclusion of chapter 54, he explained his view of the direction and nature of Gibbon's confessional inclinations: "He was a protestant by conformity, and because established protestantism, in the C18, was more liberal, more rational, more tolerant than established Catholicism. But it was not necessarily so, and if Gibbon recognised the social necessity of Reform...he would also admit that the protestant reformers enforced... ‘the absolute and essential terms of salvation..."' It was passages such as these, and the reflections they prompted, which nourished Trevor-Roper's attractive view that "Gibbon's criterion is always social or humanitarian or intellectual: it is never doctrinal."

So far we have considered only the companionable Gibbon, who echoed so many of Trevor-Roper's own preferences and convictions, and who beckoned him down the intellectual paths he was perhaps in any case inclined to follow. But now we must turn briefly to that other Gibbon, the man of consummate historical achievement, under whom Trevor-Roper's genius was to some degree rebuked. For Trevor-Roper also recognised that Gibbon's career exhibited an unusual perfection of both life and work. The years of intellectual maturity had been devoted to the work, and the work had filled the years of maturity. The Decline and Fall was a massive achievement, a triumphant example of a project of the first magnitude identified, defined and completed by the unaided efforts of its historian. Gibbon did not then go on to fritter away his energies in opuscula. After 1788, he "never contemplated another major work", as Trevor-Roper often pointed out. Gibbon had brought about "a radical reinterpretation of the process of European history" and with that, having solved "the great historical problem of his time", he stopped.

Such was not to be the shape of Trevor-Roper's own career. Although in 1944 he may have nursed the hope that he might one day write a work which posterity would place alongside the Decline and Fall, that major and defining work was never written. And even if the monograph on the Civil War over which he laboured for so many years had been completed to Trevor-Roper's satisfaction, could it ever truly have stood shoulder to shoulder with the Decline and Fall, on the terms which Trevor-Roper himself used to capture the greatness of Gibbon's book? When Hume had said of his own day that "this is the historical age", he had seen that the advanced social thought of the time had thrown up problems that demanded the arbitration of the historian, and of the historian alone. Well might Trevor-Roper wryly agree that Gibbon had drawn a high prize in the lottery of life. He had been a supremely gifted historian whose powers were at their peak when history, of all the intellectual disciplines, had the most important work to do. 

But the second half of the 20th century was not such a time. Whatever the modern equivalent was to the Enlightenment problem of progress, it was unlikely to be answered by a book on the English Civil War, no matter how accomplished. Indeed, whatever it was, it was very possibly not a problem for historians at all. Perhaps it was a problem for physicists, or biologists. The moment of history's intellectual hegemony had passed, perhaps never to return. Truly to emulate Gibbon was now impossible, and those who attempted it, such as Toynbee, succeeded in producing only gassy, shapeless, unhistorical monsters, as Trevor-Roper himself had reported in a letter to Berenson, in which superficial amusement at Toynbee's folly was chilled by an undercurrent of dismay at its significance for the writing of history. 

Trevor-Roper was too wise to fall into the gulf of uncritical complacency into which Toynbee had rushed headlong. But the price of such wisdom was to suffer a version of the last pain which Tertullian had devised for the damned — the pain of seeing, but not sharing, the pleasures of the historians' Paradise. It was for this reason that the greatest English historian of the 20th century was most at home in the form of the essay.