Clarendon to accept was a set of all the books printed at the Louvre (Evelyn, iii. 346, 446; Clarendon State Papers, iii. App. xi. xiii). Clarendon was an assiduous reader of the Roman historians. He quotes Tacitus continually in the 'History of the Rebellion,' and modelled his character of Falkland on that of Agricola. He was familiar with the best historical writers of his own period, and criticises Strada, Bentivoglio, and Davila with acuteness. Of English writers, Hooker, whose exordium he imitates in the opening of the 'History of the Rebellion,' seems to have influenced him most. But he did not disdain the lighter literature of his age, praised the amorous poems of Carew, prided himself on the intimacy of Ben Jonson, and thought Cowley had made a flight beyond all other poets. The muses, as Dryden remarks, were once his mistresses, and boasted his early courtship; but the only poetical productions of Clarendon which have survived are some verses on the death of Donne, and the lines prefixed to Davenant's 'Albovine ' in 1629.
Clarendon's 'History' is the most valuable of all the contemporary accounts of the civil wars. Clarendon was well aware of one cause of its superiority. 'It is not,' he says, ' a collection of records, or an admission to the view and perusal of the most secret letters and acts of state [that] can enable a man to write a history, if there be an absence of that genius and spirit and soul of an historian which is contracted by the knowledge and course and method of business, and by conversation and familiarity in the inside of courts, and [with] the most active and eminent persons in the government' (Tracts, p. 180). But both from a literary and from an historical point of view the book is singularly unequal. At its best Clarendon's style, though too copious, is strong and clear, and his narrative has a large and easy flow. Often, however, the language becomes involved, and the sentences are encumbered by parentheses. As a work of art the history suffers greatly from its lack of proportion. Some parts of the civil war are treated at disproportionate length, others almost entirely neglected. The progress of the story is continually broken by constitutional digressions and lengthy state papers. The 'History' was, however, originally intended rather as an exact memorial of passages ' than 'a digested relation.' It was not to be published as it stood, but to serve as 'a store' out of which 'somewhat more proper for the public view' might be collected (Rebellion, i. 3). The ' History ' itself is to some extent a manifesto, addressed, in the first place, to the king, but appealing still more to posterity. It was designed to set forth a policy as well as to relate events, and to vindicate not so much the king as the constitutional royalists. To celebrate the memories of eminent and extraordinary persons ' Clarendon held one of the principal ends of history. Hence the portraits which fill so many of his pages. His characters are not simply bundles of characteristics, but consistent and full of life, sketched sometimes with affection, sometimes with light humour. Evelyn described them as 'so just, and tempered without the least ingredient of passion or tincture of revenge, yet with such natural and lively touches, as shew his lordship well knew not only the persons' outsides but their very interiors; whilst he treats the most obnoxious who deserved the severest rebuke, with a becoming generosity and freedom, even where the ill-conduct of those of the pretended loyal party, as well as of the most flagitious, might have justified the worst that could be said of their miscarriages and demerits.' Clarendon promised Berkeley that there should not be 'any untruth nor partiality towards persons or sides ' in his narrative (Macray, Clarendon, i., preface, p. xiii), and he impartially points out the faults of his friends. But lack of insight and knowledge prevented him from recognising the virtues of opponents. He never understood the principles for which presbyterians and independents were contending. In his account of the causes of the rebellion he under-estimates the importance of the religious grievances, and attributes too much to the defects of the king's servants, or the personal ambition of the opposition leaders.
As a record of facts the 'History of the Rebellion' is of very varying value. It was composed at different times, under different conditions, and with different objects. Between 1646 and 1648 Clarendon wrote a ' History of the Rebellion' which ended with the defeat of Hopton at Alresford in March 1644. In July 1646 he wrote, by way of defending the prince's council from the aspersions of Goring and Grenville, an account of the transactions in the west, which is inserted in book ix. Between 1668 and 1670 he wrote a 'Life' of himself, which extended from 1609 to 1660. In 1671 he reverted to his original purpose, took up the unfinished ' History ' and the finished 'Life,' and wove them together into the narrative published as the 'History of the Rebellion.' During this process of revision he omitted passages from both, and made many important additions in order to supply an account of public transactions between 1644 and 1660, which had not been treated with sufficient fulness in his `Life.'