In his Dialogue, probably written between 1419 and 1421, Thomas Hoccleve cites one of the most important military manuals circulating in the Middle Ages: Vegetius' De re militari. On the one hand, this reference simply serves as a compliment to Humphrey, duke of Gloucester's martial prowess: Humphrey is such a good military commander that he can afford to ignore perhaps the most influential military handbook of his time. Hoccleve presents De re militari as an educative, didactic text; one that can teach ‘the art of chiualrie’ to those less well ‘preeued’ in the art of war than Humphrey. Yet, Hoccleve's representation of De re militari as a text which would have been translated were it not for Humphrey's martial skill points, perhaps unconsciously, to an alternative situation that would necessitate the translation and reading of Vegetius: a context in which there was a lack of military ‘maistrie’, an insufficiency in, or ignorance of, the art of war. Such ignorance might even lead to military defeat, the proof of which would lie, not in the citation of the conquest of Cherbourg ‘among othre’ towns, but in a catalogue of failed sieges and lost territories.

In the prologue to his Troy Book, the poet John Lydgate offered the following commendation of his patron, Prince Henry, the future Henry V:

In this passage, Lydgate fuses Henry's martial practice, his ‘excersice’ and ‘pleies marcyal’, with the theory or ‘doctrine’ of war advanced by Flavius Vegetius Renatus, the author of a Latin treatise on warfare known as De re militari. Lydgate's use of Vegetius in this passage points to De re militari's status as perhaps the most authoritative military manual of the Middle Ages.

This was not the first time that Vegetius' name had been utilised in this way by an English poet during the course of the second decade of the fifteenth century. As discussed above, Lydgate's contemporary, Thomas Hoccleve, also referred to Vegetius in his ‘Address to Sir John Oldcastle’, written in 1415: ‘Clymbe no more in holy writ so hie!’, Hoccleve advised the rebel Lollard knight, but rather ‘Rede the storie of Lancelot de lake, / Or Vegece of the aart of Chiualrie’. Towards the end of the decade, Vegetius appeared again in Hoccleve's verse, in his Dialogue, probably written between 1419 and 1421. Henry himself may have been present at the Epiphany sermon delivered in 1414, in which the preacher urged ‘knyʒtes and oþur gentils’ to consider the ‘many sotell questions and conclusions in mater of werre and armes’ found in Vegetius' De re militari and Giles of Rome's De regimine principum.

While the rhetoric generated by Henry's wars in France clearly informed the way that Lydgate wrote about war and its prosecution in Troy Book and the Siege of Thebes, the presence of military conflict in England several decades later helped to produce one of the most brilliant military poems of the fifteenth century: an ambitious translation and rewriting of Vegetius' De re militari, replete with Latinate vocabulary and rendered in rhyme royal, and now known as Knyghthode and Bataile. This extraordinary translation of De re militari, completed at some point between November 1459 and July 1460 by an anonymous translator who tells us that he is a ‘person of Caleys’ (line 33), was no straightforward ‘Englishing’ of a source: this author-translator succeeded in producing a text which, while having much to offer in terms of military insight and advice, also advanced a trenchant argument in support of Henry VI's government and against those who opposed it. Harnessing the representational mode of civic entry and the language and imagery of spiritual warfare, this author both urged the importance of firm military action against the Yorkist lords, while also investing such an enterprise with a crusade-like urgency and salvific value. In so doing, the author went beyond most other Lancastrian polemicists by constructing Henry's opponents not only as ideologically bankrupt, but also as heretical and akin to the archetypal traitors, Lucifer and Judas.

This chapter draws attention to the religious and military imagery found in Knyghthode and Bataile and shared by a range of contemporary works, and maps the various rhetorical strategies at play in this remarkable poem.

At a combined 34,833 lines, John Lydgate's Troy Book (1412–1420) and Siege of Thebes (c. 1422) rank as two of the lengthiest and most ambitious works of Lydgate's massive literary output. Although they have received a relatively large amount of critical attention from scholars, debate has tended to focus on two related issues. First, critics have attempted to determine how far Lydgate was complicit with the agendas of his patron, Henry V and, in the case of Siege of Thebes, seemingly written without a specific commission, with the ideologies and strategies of the ‘Lancastrians’ more generally; and second, criticism has centred on the degree to which Troy Book and Siege of Thebes can be seen to support or critique Henry's wars in, and policies towards, France.

For Paul Strohm, for example, Lydgate ‘sought consistently to advance Henry's prospects, first as Prince and then as King Henry V, as well as those of his infant son’ and he argues for the ‘complete identification’ of the Siege of Thebes ‘with Henry V's ambitions in France’. Strohm characterises both Lydgate and his contemporary Thomas Hoccleve as attempting to be ‘as complicit as possible in every aspect of the Lancastrian program’. For James Simpson, on the other hand, Lydgate ‘was not by any means a propagandist poet’; rather, his Troy Book and Siege of Thebes are ‘consistently anti-imperialistic’. According to Simpson, the Siege of Thebes ‘offers an extremely powerful admonition against lightly taking on war, whether civil or against France, whatever the perceived justice of the cause’.

In his ‘Address to Sir John Oldcastle’, the poet Thomas Hoccleve offered the following advice to the heretical, rebel knight:

Reading occupies a central place in the programme of correction and reform that Hoccleve recommends for Oldcastle. Rather than continuing to ‘Clymbe … in holy writ so hie’, Oldcastle should read stories about Lancelot, the sieges of Troy or Thebes, or a version of the late Roman military handbook, De re militari (‘Vegece of the aart of Chiualrie’). Reading is figured here as corrective, as an activity which might enable Oldcastle's ‘correccioun’. The texts that Hoccleve recommends are the textual embodiments or representatives of those things that belong ‘to thordre of knyght’, to which things Oldcastle is urged to ‘applie’ himself. Reading is here imagined as an active process, in ways which recall Grafton and Jardine's formulation of texts being ‘studied for action’, and is intimately connected to self-transformation. The reading of these texts and presumably the reading of Hoccleve's own poem will enable Oldcastle to fashion himself as the ‘manly knyght’ (line 9) he once was and will lead to his ‘correccioun’, just as his reading of ‘holy writ’ led to his error.