IIRC, according to Fry, Petrarch invented the sonnet, and the rhyme scheme worked well for the Italian language.
A quatorzain is 14 verse poem. While most sonnets are quatorzains, not all quatorzains are sonnets. What destinguishes the sonnet is a progressive narrative and stylistic implementation of the dialectical turn (aka Volta); it's one of the foundations of its initial purpose.
The sonnet is one of the oldest and most recognisable verse forms still flourishing in the modern world. Born out of song and expressing a variety of themes and narratives, it has evolved into one of the most flexible and thematically approachable templates for composing poetry, and has spawned several genres of sub-variants and stylisations beyond the standard verse form of its origin.
Today, ‘sonnet’ has become an umbrella term for the many child-forms that have matured over the centuries through formalisation and mould-breaking experimentation. The form itself was the product of folk song and troubadouric verse presented to the aristocracy by 13th century Poet (and notary to the Court of Holy Emperor Fredrick II), Giacomo Da Lentini, aka Jacopo Da Lentini. Despite the customary feudal and chivalrous thematic expected from poetry of his time, a recurring undertone of Da Lentini’s poetry was a persistent sense of discord between poet and subject. Each of his works resulted in a conflict or debate. It is idealised by scholars that Da Lentini’s academic credentials and consequential familiarity with the elegiac couplet of Hellenistic prevalence, and the rising interest for new ideas leading into the renaissance period collided to form the basis of what is known formally as the Volta (or turn). Lentini didn't write many quartorzains, and his sonnets range from 13 to 36 verses.
14th century poet, Francesco Petrarca (Anglicized, Petrarch) is referred to as the grandfather of modern poetry, and also the father of humanism – formerly a priest, and a scholar, Petrarch’s views on life and humanity heavily influenced his poetry. The non-secular humanist nature of his themes (the trend of poetry more diverse than 100 years earlier) delved into both sensibility and emotion. This contrast was further embellished by progressive narrative in 14 verses of 11 syllables that led into the juxtaposition of either concept through the Volta as re-defined by Petrarch.
Petrarch’s Volta set formalisation of the sonnet in motion with his new sonnet adopting a more deliberate architecture than its predecessor: 8 verses (an octave/octet rhymed abbaabba) and 6 six verses (a sestet rhymed either cdecde; cdcdcd; cddece). The Volta occurred explicitly to begin the 9th verse. Although commonly presented as a single stanza the ‘eight and six’ had deeper purpose than a shifted rhyme scheme. The octet presents a supposition, a point of concern/thought in its first verse, and elucidates in the following 3 progressively to formulate an argument by the 8th. The sestet initiates a counter-thought at the 9th verse, signalling the Volta with the new rhyme, and progresses to a resolve by the 14th. Petrarch avoided closing with a couplet as doing so would be too deliberate, and the philosophical aspect would be rendered mechanical.
Not only did Petrarch solidify the dialectical turn, but his method for structuring lines outside of ‘majestic’ custom (end-stopped; complete thought per verse) opened them to enjambment, and allowed for a less contrived tone.
The truth-seeking, internal musing of Petrarch’s poetry became a catalyst for many lyrical poets that followed in the renaissance and throughout the 14th and 16th centuries. However, the relative rhyme-anaemia of the English language and awkward 11 syllable line measure made writing the Petrarchan an arduous task. Poets responded by adapting and reworking the metre and rhyme to suit their language. Shakespeare's variant is the most common re-imagining of the sonnet still. These fledgling sonnets grew in popularity, steamrolling through literature – the Petrarchan left behind until resurrected by Milton’s revision of it in the mid 17th century.
Nuns fret not at their convent's narrow room by William Wordsworth
Nuns fret not at their convent's narrow room
And hermits are contented with their cells;
And students with their pensive citadels;
Maids at the wheel, the weaver at his loom,
Sit blithe and happy; bees that soar for bloom,
High as the highest Peak of Furness-fells,
Will murmur by the hour in foxglove bells:
In truth the prison, into which we doom
Ourselves, no prison is: and hence for me,
In sundry moods, 'twas pastime to be bound
Within the Sonnet's scanty plot of ground;
Pleased if some Souls (for such there needs must be)
Who have felt the weight of too much liberty,
Should find brief solace there, as I have found.
John Milton changed how prosodists and enthusiasts viewed the sonnet a century before Wordsworth wrote ‘Nuns fret not at their convent's narrow room’, in particular the implementation of the Volta. The revived form (Miltonic Petrarchan) allowed for the Volta to be enjambed from before or after the 9th verse; pre-emptive in an earlier verse; for the 9th verse to set up the Volta for a later point; delay it until the end; the entire sestet to become the Volta (= peripeteia) or even ignore it altogether – the new eight and six only deemed it necessary to hold separate thoughts respectively, not necessarily in contrast, resolve, or reaction, but simply capturing a moment of thought/reflection. This liberation was championed by Wordsworth more than any other poet of his day – as can be seen in ‘Nuns fret not at their convent's narrow room’ by the Volta enjambed over into verse 10. Many used the ideal of that respective split to open up and re-direct their narrative to use the sonnet in a manner that avoided the expected internal conflict:
Nuptial Sleep by Dante Gabriel Rossetti
At length their long kiss severed, with sweet smart:
And as the last slow sudden drops are shed
From sparkling eaves when all the storm has fled,
So singly flagged the pulses of each heart.
Their bosoms sundered, with the opening start
Of married flowers to either side outspread
From the knit stem; yet still their mouths, burnt red,
Fawned on each other where they lay apart.
Sleep sank them lower than the tide of dreams,
And their dreams watched them sink, and slid away.
Slowly their souls swam up again, through gleams
Of watered light and dull drowned waifs of day;
Till from some wonder of new woods and streams
He woke, and wondered more: for there she lay.
The Miltonic liberties were fed back into the Sonnet in other languages also, and even the purists found themselves playing and reworking the verse form to suit theme and language wherever required. Some poets, such as Shelly, even fused elements from other verse forms (Terza Rima for example) into the 14 line structure.
The Miltonic Petrarchan is still a common and widely used variant of the sonnet and has been used by many highly regarded poets of the 20th century such as Robert Frost. Frost regarded himself a 'furiously experimental' formalist, a statement we see echoed within all of his verse (sonnet or otherwise), but nowhere moreso than in his adaptations of quatorzain and sonnet. For a long time, Frost's 14 verse poetry has been viewed by prosodists as quatorzains, but the recent universal reclassification recognising his work as sonnets makes him one of the most prolific sonneteers of the last 100 years:
I have been one acquainted with the night.
I have walked out in rain — and back in rain.
I have outwalked the furthest city light.
I have looked down the saddest city lane.
I have passed by the watchman on his beat
And dropped my eyes, unwilling to explain.
I have stood still and stopped the sound of feet
When far away an interrupted cry
Came over houses from another street,
But not to call me back or say good-bye;
And further still at an unearthly height,
One luminary clock against the sky
Proclaimed the time was neither wrong nor right.
I have been one acquainted with the night.
Then there are those that completely
re-invented the sonnet (think Gerard Manly Hopkins).
What made it hard for Frost was that he frequently has no identifiable turn. Despite this, though, his poetry often ends in counter-point to where it starts. He achieves this through convex and paradoxical language based on context and meaning.
I have no doubt the same is-a-sonnet-not-a-sonnet arguement has been applied to many of the greats for similar reasons.
In any case, if you start off writing a sonnet that turns out a quatorzain (see what I did there?
), or anything else, who really cares? It's your poem, and you'll be in good company.
_____________________
ETA: there are sonnets of 6 lines, 8 lines, 10, 12 lines, 17 lines and even 27 lines. 14 is an ideal and popular number, but by no means an absolute.
As for meter:
http://www.absolutewrite.com/forums/showthread.php?t=236884