Epics are commonly referred to as encyclopedic, so implying qualities such as comprehensiveness, variety, and scope that require integration. The tension between unity and variety takes many forms and may lead to such disputes as whether Lucan's Pharsalia is a loose historical poem rather than an integral epic. At the heart of these assumptions are two issues: what is the regular or necessary by which the irregular becomes unwanted, and what are the true grounds of a true epic? If full assurance seems a vain hope, it is striking to observe the comfort Milton enjoyed. Through that lengthy career of changes in his religious and political beliefs, he claimed “truth” as a familiar, constant possession. And yet in addressing his ideas of the regular and irregular in epic poetry, even he had a moment of unanswered questioning of what an epic should be. That came, it will be recalled, in his Reason of Church-Government (1642). The issues involved
what the mind at home in the spacious circuits of her musing hath liberty to propose to her self, though of highest hope, and hardest attempting, whether that Epick form whereof the two poems of Homer, and those other two of Virgil and Tasso are a diffuse, and the book of Job a brief model: or whether the rules of Aristotle herein are strictly to be kept, or nature to be follow'd, which in them that know art, and use judgement is no transgression but an inriching of art. And lastly what K[ing] or Knight before the conquest might be chosen in whom to lay the pattern of a Christian Heroe.(CPW 1.812–14)
For his epic Milton has an obliging Muse who “inspires / Easie my unpremeditated Verse” (9.23–24). The ease of his “unpremeditated Verse” does not apply to calm of mind about the versification of his epics. So we quickly discover in reading “The Verse, ” that label given some two dozen lines of prose added to deal with the problem that his publisher said had stumbled contemporary readers, “why the Poem Rhimes not.” The answer is given straight off: “The Measure is English Heroic Verse without Rime, as that of Homer in Greek, and of Virgil in Latin”(Works 2.pt.1.6; italic usage reversed). These poets and Tasso had been the models for epic which Milton contemplated in writing The Reason of Church-Government, and if the Italian is no longer adequate, that is obviously because of his use of rhyme. Of course Milton continued to admire and to need Tasso for other reasons. But Paradise Lost is “an example set, the first in English, of ancient liberty recover'd to Heroic Poem from the troblesom and modern bondage of Rimeing” (ibid.). Rhyme is a modern barbarism, whereas this unrhymed and yet more modern epic recovers the true original, the prisca veritas. How reforming, how Protestant this is. (For other issues of the first, see Excursus 6.327.)
Our words “regular” and “irregular” of course derive from Latin “regula, ” rule, pattern, or model. Milton turns regularity and irregularity inside out. What had been regular (rhymed verse) is presented as irregular on the basis of temporal and more particularly qualitative and veridical grounds. What is regular about Paradise Lost is that it “Rhimes not” and rejects the gorgeous fiction of chivalry along with war as a subject. Those very features of the poem that make it hardest to put it in the line of Renaissance and classical epics are taken to be the normal ones. (What had been regular is now irregular, and that unheard of—religious epic in unrhymed vernacular verse—is now regular.) We must accept in poetic faith the new claim to what constitutes, if solely for Milton's practice, epic regularity and irregularity.
It cannot be said that Milton made blank verse the rule. Apart from the disasters suffered by his imitators, the two greatest translations of epic in English— Dryden's Virgil and Pope's Homer—postdate Paradise Lost and yet are in rhyme. But such is the indisputable greatness of Paradise Lost that in its wake rhymed heroic verse in English was no longer the sole expectation. Milton also brought about a change in the nature of possible regularity that implied new possibilities for irregularity. If Paradise Lost is regular, the presence of rhyme becomes an irregularity.
It is a tribute to the strength of the regular and expected that a heightening of rhyme in rhymed verse is more readily observed than occasional rhymes in unrhymed verse. Dryden's triplets, with the third line so often an alexandrine, are so conspicuous that they often feature in imitations of his style, as imitations of Milton's involve verbal stilt walking and placing adjectives after their nouns.