Blank verse is often confused with free verse, though they actually have nothing in common except the fact that neither rhymes.  Free verse is a medium for an era that has little understanding for or appreciation of the magical and incantatory nature of poetry.  It avoids all of the various patterns of repetition which have been central to the various poetic languages of the world and substitutes instead a loose and varying rhythm that in many cases differs from prose only in that the lines do not come out to the end of the page.  Early in the 20th century such poetry in the hands of poets like Eliot and Pound sounded fresh and original.  These poets, however, had ears trained by more traditional forms and could write lines that were clean and crisp and graceful.  The generations that followed, without such a background mostly lack the ear to write free verse effectively and the technique to write traditional verse.  One result has been that today there are probably more people writing poetry than there are willing to read it.
     Blank verse, on the other hand is a traditional form--unrhymed iambic pentameter.  In theory it consists of ten syllables made up of five pairs of syllables, the first unstressed, the second, stressed.  In practice a passage of iambic pentameter is made of lines that range from nine to eleven syllables with five stresses to each line, though not all arranged in an iambic ( x / ) pattern.  The perfectly regular iambic pentameter line lies like a bass line behind the verse, but is seldom followed exactly.  We seem to have some inner sense of iambic rhythm, for we hear it in the tick-tock of every clock, though in reality the sound is only in our ear.  There is no actual difference between the ticks and the tocks; we merely impose the rythm upon them.  Speaking of clocks, here is an amost perfect imabic pentameter line from Shakespeare:  "How do I count the clock that tells the time."  Here we have the pattern in almost pure form-- x / x / x / x / x /.  It doesn't really sound very appealing does it?  Shakespeare is obviously playing off the clock image with a tick-tock rhythm.  Perhaps as compensation the next "iambic pentameter" line is almost unscannable:  "And see brave day sunk into hideous night."  I think the stress pattern of this is something like x / \ / / x x / x /.  The word "brave" is about half-way stressed, but falling between two stresses serves as an unstressed syllable.  Shakespeare probably read "hideous" as a two syllable word, though it does not matter greatly.  In this line there are ten or eleven syllables and five stresses.  Standing alone it could not really be called iambic pentameter, but as part of a poem with that meter as a bass or base line, it is.  One of the unfortunate features of many school books that have a unit on poetic forms is that they often quote lines and mark the stresses in a way that follows the proper pattern, but that is not at all the way anyone would really read the line.
     Once when I was teaching a creative writing class I decided to explain meters, and  for iambic pentameter chose Robert Frost.  Most of his longer poems are in this form and, as everyone knows, Frost is very regular in his patterns.  I opened a literature survey to Frost's "Mending Wall," confident that here would be a clear example.  The first word of the poem was "Something."  You might possibly force the word into "sum-Thing," but no one really would.  The first iambic foot of the poem was reversed, though the rest of the line was regular enough.  I tried the second line:  "That sends the frozen-ground-swell under it."  I didn't even try to do the metrics of this line.  I tried the third:  "And spills the upper boulders in the sun."  This would almost do.  The problem is that it is only our underlying expectation of a stress that puts a stress on "in" which is weak in itself, and is part of a very non-iambic unit--"in the sun," which would normally be stressed x x /.  Line four was seriously irregular.  Line five was close, though it stressed a weak "is."  Lines six, seven, and eight were all seriously irregular.  Finally, with line nine I almost had what I wanted:  "To please the yelping dogs.  The gaps, I mean."  We do play down the "I" to humor the meter, but altogether, this is pretty close.  My point here is not that Frost is less traditional than his reputation, but rather that English iambic pentameter leaves the writer about as much freedom as anyone could ask for.
     No poet in English is more strongly identified with blank verse than Milton, who first made it the norm in English for epics and other long poems.  Before Milton, though blank verse was used for dialogue in most drama, it had not been used for long poems or even for translations of long poems, though today it is nearly always used if prose is not.  We can see, however, in the very first line of Paradise Lost, however, that Milton is not more regular than Frost in his usage:  "Of man's first disobedience and the fruit."  Milton does compensate with a fairly regular second line:  "Of that forbidden tree, whose mortal taste."
       Aside from popularizing blank verse, Milton also deserves credit for showing a way the deficiencies of the form can be overcome.  The reason blank verse was used for dialogue is that it is a fairly faint rhythm, not too obviously different than that of normal speech.  Not only is the iambic unemphatic, but so is the pentameter.  The normal rhythm in English seems to be the four stress line.  The other most natural rhythm is a four stress line alternating with a three stress line, which in English is called ballad meter.  In Old Norse, like English, a Germanic language, there is a close equivalent with ljodahattr meter which also alternates a four stress line with a three stress line and is often used for ballad-like poems.  The five stress line does not come naturally and does not create a strong rhythm.  One can write so much of it that it becomes second nature, but it is a learned talent that no one does naturally.  Thus the danger of blank verse is that it will become flat and monotonous, and in fact if often does, especially in a long poem.  Frost overcomes that problem by having a good ear for voice tones, so that his verse seems to speak to us in a natural way.  Milton, on the other hand, makes it work by a richness of language, and by making one line rush into the next without the usual hesitation, so that there is always a sense of pressing forward.  In Milton, for the first time, the paragraph becomes a real unit of the verse, for we have to wait for the end before we can really pause:
Of man's first disobedience and the fruit
Of that forbidden tree whose mortal taste
Brought death into the world, and all our woe,
With loss of Eden, till one greater Man
Restore us, and regain the blissful seat,
Sing, Heavenly Muse, that on the secret top
Of Oreb, or of Sinai, didst inspire
That shepherd who . . .
     Blank verse was a slow starter in America.  In the seventeenth century the puritan New Englanders, when the wrote poetry at all, mostly followed the rather harsh lyricism of the English "Metaphysical" poets.  In the eighteenth they were mostly feeble imitators of the manner of Dryden and Pope and wrote heroic couplets.  In the nineteenth it was mostly rather tame, though often proficient imitations of the romantics.  For most Americans, poetry = rhyme.  Thus blank verse was a mysterious, very highbrow thing.  Making poetry rhyme was an art, but making it not rhyme was a mystery.  The great blank verse classic for America was William Cullen Bryant's "Thanatopsis," which not only didn't rhyme but also had a title in Greek, and one that meant "Prospect of Death."  You couldn't possibly get more POETIC!! than that.  It is eighty-one lines long, big enough to be impressive, but not long enough to outrun the limited attention span of the ordinary reader.  Though the poem is a huge cliche with a thorougly overblown reputation, it is actually pretty proficient, and worth reading.  More than anything, what killed its mystique was the arrival of modernism which produced a lot more poems that didn't rhyme.  It has been replaced especially by Eliot's Wasteland, which not only doesn't rhyme (most of the time), but which also has footnotes and is lots harder to understand, two other big plusses on the impressiveness scale.
     Actually, to say that Bryant's poem is proficient is saying quite a bit.  Many poets today, even fairly good ones seldom write a line of ten syllables, and of the ones that do, many of the lines are obviously patched together from pieces like Frankenstein's monster, rather than having any real organic integrity.  There is real power in being able to make a line which ends the line above it and begins the one below it, and still has a sense of completeness, like Milton's "Of that forbidden tree, whose mortal taste."  Here is the beginning of Bryant's poem:   
     The poet in English most identified with perfectionism in his meter and his appropriateness and exactness of rhymes is Alexander Pope.  Most of what Pope wrote, and all the best of it was in iambic pentameter lines, though not in blank verse, but in the closed, or heroic couplet.  Oddly, Pope's great epic poem on the founding of Britain was to be in blank verse.  It would have been interesting to see the results, but he only lived to finish the first six lines, though the poem had been thorougly outlined.  I recall reading various Victorian critics who were mostly hostile to Pope's poetry.  I think two different ones, though I can't now remember who described how Tennyson was first enamored by Pope but became put off by his monotonous regularity and struck out on his own.  That is a charge that shows that criticism could be as ignorant and absurd in the past as it is now.  First, Pope has a far better ear and produces far more subtle effects than Tennyson.  Second, Pope, like all significant English poets uses the ten syllable line with considerable freedom.  In the passage below, only the last line is solidly regular:
Shut, shut the door, good John! (fatigued, I said),
Tie up the knocker, say I'm sick, I'm dead.
The Dog Star rages! nay 'tis past a doubt
All Bedlam or Parnassus is let out:
Fire in each eye, and papers in each hand,
They rave, recite, and madden round the land.
                                                         Epistle to Arbuthnot
     I will finish with something a little like a crude bibliography.  From the earliest plays on, nearly all Elizabethan plays use blank verse.  After 1660 comedy went to prose, but blank verse remained in use for tragedy into the eighteenth century.  An exception was the short-lived popularity of Heroic Plays which were written in rhymed couplets.  Milton's Paradise Lost, Pardise Regained, and Samson Agonistes were all in blank verse.  James Thompson's Seasons pioneered nature poetry for the eighteenth chentury.   A number of other long and influential poems of the eighteenth century were written in blank verse as well.  Some of these had a major impact on the Romantic revolution in Germany as well as in England.  Edward Young's enormous poem (long enough that William Blake provided 537 watercolor prints for it) Night Thoughts had a great effect on the Sturm und Drang movement in German literature, and was still considered a major work long after it was nearly forgotten in the English speaking world.   Wordsworth's long, autobiographical poem, The Prelude is in blank verse.  Browning's dramatic monologues are all in blank verse.  Frost's longer poems are in blank verse.  Steven Vincent Benet's once widely popular epic, John Brown's Body  is in blank verse, as have been most efforts in the last two centuries to write an epic.  Edward Arlington Robinson's book-length romance, Tristram, as well as Tennyson's romance/epic Idylls of the King are also blank verse.  Edward Markam's "The Man with a Hoe" was a blank verse Marxist classic for the first part of the twentieth century, but has slipped into obscurity as well as Edgar Lee Masters' once wildly popular people's epic, Spoon River Anthology.  There is much, much else less well known, as well as a number of important works I have no doubt forgotten to mention.   --Jack Hart
     On the whole, however, the eighteenth century was more concerned with proper form than other eras.  It was big on rules, so of course had rules for exceptions.  One of the permissible exceptions for the ten syllable line was the Alexandrine--a twelve syllable line with six stresses.  Sir Philip Sydney has a whole sonnet in twelve syllable lines, and we see them now and then elsewhere.  In French it is fairly common, both for sonnets and elsewhere.  Either the French have a real difference in taste about what sounds good, or French is able to accomodate a longer iambic line more comfortably than English can.  My French is not proficient enough to judge, but it seems to me a worthwhile question.
To him who in the love of Nature holds
Communion with her visible forms, she speaks
A various language; for his gayer hours
She has a voice of gladness, and a smile
And eloquence of beauty, and she glides
Into his darker musings, with a mild
And healing sympathy, . . .
     This all reads pretty well.  You have to get down to the next to last line of this passage to find a line that will not stand by itself, and in which the metrics don't entirely work.  Into is ambiguous--where does the stress fall, and is his stressed or not?  With is a very weak word to bear a stress, and it only manages it because Bryant has added an even weaker a to follow it.  Still, the line does not read as badly in context as it does alone.
     The button labeled "Poetry" above and on the left leads to a page about my poetry magazine, Ship of Fools.  Some other relevant pages are indicated below.
This is the index page for the several pages on this site dealing with creative writing and the conventions of publication.
This page describes the conventions of submitting poetry for publication, as well as giving some idea of what goes on in an editor's head.
This page, "Death in the Country" is a small collection of my poems dealing with death in a rural setting.  The subject must be a downer; it has never attracted may visitors.
     By the time Milton began his epic, however, blank verse had already had a century of history on the stage where Peele, Kyd and others had shown that the form was adequate for most of what they wanted to do--natural enough for dialogue, but capable of rhetorical elevation when need be.  Starting with Tamburlaine in 1587, however, Christopher Marlowe showed that the form could be more than adequate.  Marlowe's blank verse has a rich rolling cadence and a rhetorical grandeur that had not been been heard before.  Here is a famous passage from Dr. Faustus:
Was this the face that launched a thousand ships,
And burnt the topless towers of Ilium?
Sweet Helen, make me immortal with a kiss:
Her lips suck forth my soul, see where it flies!
Come Helen, come, give me my soul again.
Here will I dwell, for heaven be in these lips,
And all is dross that is not Helena!
I will be Paris, and for love of thee,
Instead of Troy shall Wittenberg be sacked;
And I will combat with weak Menelaus,
And wear thy colors on my plumed crest:
Yeah, I will wound Achilles on the heel,
And then return to Helen for a kiss.
O thou art fairer than the evening air,
Clad in the beauty of a thousand stars,
Brighter art thou . . .
                         Faustus, Scene 13, ll. 80-95
     Shakespeare's version of blank verse is quieter and less grandly rhetorical.  For what, at least to me, appears to be a parody by Shakespeare of the Marlowe manner, see the long Hecuba speech in Hamlet.  Below is an example of Shakespeare's mature blank verse:

Our revels now are ended.  These our actors,
As I foretold you, all were spirits, and
Are melted into air, into thin air:
And, like the baseless fabric of this vision,
The cloud capp'd towers, the gorgeous palaces,
The solemn temples, the great globe itself,
Yea, all which it inherit, shall dissolve,
And, like this insubstantial pageant faded,
Leave not a rack behind.  We are such stuff
As dreams are made on, and out little life
Is rounded with a sleep.
                                          Tempest  IV:1

This link is to a page on poetic meter, 
which greatly expands upon the content of this page.
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