And if no peece of Chronicle wee prove,
We'll build in Sonnets pretty roomes;
As well a well wrought urne becomes
The greatest ashes, as half-acre tombes...
(John Donne, 'The Canonization')
The sonnet is Donne's 'well wrought urne' - compact, shapely, highly finished, and able to contain, in concentrated form, almost all that is human.
Michael R.G. Spiller, The Development of the Sonnet (London & New York, 1992), page 1.
Or in modern times, perhaps we could think of the sonnet as a crafted piece of furniture, combining art, skill, beauty, function and that indefinable quality that speaks to us of more than the sum of the parts.
Writing a 'traditional' sonnet, though, has similarities with doing a crossword. It is a puzzle to make the pieces fit; there is some intellectual tease, and you can mull over individual lines, like crossword clues, as you continue daily life. There is also a knock-on effect. If you change a line, other lines then may need to change, just as changing the answer to 7 across in a crossword may mean you have to rethink 4 down. It is interesting as a form of poetry in which, at least in traditional form, structure and meaning are very intricately bound together and writing sees an ever shifting balance between the two as the poem works out what it is to be.
The sonnet is one of the longest lived of all poetic forms. It appears to originate in the Kingdom of the Two Sicilies (Sicily itself and the southern half of Italy) under the rule from 1208 to 1250 of The Holy Roman Emperor Frederick II. 35 sonnets survive from this period of which 25 are usually attributed to the notary and legal deputy of the Emperor named Giacomo da Lentino. He may be regarded as the 'inventor' of the form, although many preceding influences could be discussed for which there is no space here.
The perfecter of the sonnet in Italian is agreed to be Francesco Petrarca (1304-1374), otherwise known as Petrarch. The distinctive rhyming pattern of a Petrarchan sonnet is abba abba and then either cdcdcd or cdecde. With an alternative opening of abab abab, this pattern remained the template for the European sonnet until Sir Thomas Wyatt 'reinvented' the rhyming couplet as an ending (a minor Italian poet, Nicolo de'Rossi, c. 1285 - 1335, had done this before but it had not caught on with his contemporaries). After Wyatt's re-inroduction of the closing couplet, the form was adopted by most British sonneteers, so one typically finds abba abba cdcdee or abab abab cdcdee
Edmund Spenser (1552?-1599) introduced a more convoluted rhyming scheme of abab bcbc cdcdee, but there were few followers. Sir Philip Sidney ( 1554-1586) experimented in his Arcadia with some rather extraordinary rhyme schemes, such as a single rhyme for all fourteen lines and abab baba acaccc, but his great sequence Astrophel and Stella consistently uses an 'Italian' octet (abba abba) and an 'English' sestet (cdcdee or variants).
The form we now know as Shakespearean - abab cdcd efefgg - was actually established by the Earl Surrey (1517?-1547), but the quality and perhaps also quantity of Shakespeare's sonnets has resulted in his name bearing the laurels for this pattern. In English the Shakespearean form is the most widely imitated of traditional forms, possibly because it is less demanding on rhyme in a language that has nowhere near the number of rhyming words that, say, Italian has.
Italian sonnets tend to have 11syllables (excluding elisions) in each line, while English sonnets tend to have 10 syllables per line in an iambic pattern (unstressed syllable, stressed syllable), although most poets will play with metre at one time another. One of the points about repetitive metric patterns, just like beats in music, is the opportunity they create to suddenly change the pattern or beat for effect, whether that be emphasis, surprise, a sense of speeding up or slowing down, etc.
If you are really interested in the history of the sonnet, we recommend Michael Spiller's book cited at the top of this page (ISBN 0-415-07744-3 & 0-415-08741-4 pbk) from which much of the above has been gleaned. You may also wish to look at www.sonnets.org, and there are many other sites devoted to sonnets on the Internet.
A final word. The Open Poetry competition will treat traditional/formal sonnets and freeform/innovatory sonnets on an equal basis. Whatever the structural form, the quality of the sonnet as poetry is paramount and poetry is more than either form or content in themselves.
[If you are new to the use of letters to designate rhyming schemes, the first line rhyme is marked as a and any line that rhymes with that is also designated as a. The next new rhyme is b and any lines rhyming with that are also b, and so on to line 14, each new rhyme moving on a letter.]