More than any other form, the sonnet is the most important in the eyes of ETS. Take pains to memorize the differences between the Italian, English, and Spensarian sonnet. This will help you not only on questions that directly address form and authorship, but it will help you contextualize questions generally. I have included in this section the curtal sonnet, which was invented by Gereard Manley Hopkins; however, ETS may not acknowledge the curtal sonnet as equal to other sonnet forms.
The Princeton Review book does a very good job of succintly breaking down the differences between sonnet forms, so I highly suggest you take a look at their breakdown.
There are two really important things to know about the Italian sonnet:
rhyme scheme: a-b-b-a, a-b-b-a, c-d-e, c-d-e.
Broken up into an octet and a sestet.
The major Italian sonneteers included Dante Alighieri (1265–1321) and Guido Cavalcanti (c. 1250–1300), but the most famous early sonneteer was Francesco Petrarca (1304–1374).
In its original form, the Italian sonnet was divided into an octave followed by a sestet in the topic or tone of the sonnet. The octave stated a proposition and the sestet stated its solution with a clear break between the two. Typically, the ninth line created a "turn" or volta, which signaled the move from proposition to resolution. Even in sonnets that don't strictly follow the problem/resolution structure, the ninth line still often marks a "turn" by signalling a change in the tone, mood, or stance of the poem.
Giacomo da Lentini octave rhymed a-b-a-b, a-b-a-b it became later a-b-b-a, a-b-b-a. For the sestet there were two different possibilities, c-d-e-c-d-e and c-d-c-c-d-c. In time, other variants on this rhyming scheme were introduced.
The first known sonnets in English, written by Sir Thomas Wyatt and Henry Howard, Earl of Surrey, used this Italian scheme, as did sonnets by later English poets including John Milton, Thomas Gray, William Wordsworth and Elizabeth Barrett Browning. However, these poets tended to ignore the strict logical structure of proposition and solution. (ETS may refer to sonnets with an Italian form but not break between the octet and sestet as a "Miltonic sonnet").
This example, On His Being Arrived to the Age of Twenty-three by Milton, gives a sense of the Italian Form:
How soon hath Time, the subtle thief of youth, (a)
Stolen on his wing my three and twentieth year! (b)
My hasting days fly on with full career, (b)
But my late spring no bud or blossom shew'th. (a)
Perhaps my semblance might deceive the truth, (a)
That I to manhood am arrived so near, (b)
And inward ripeness doth much less appear, (b)
That some more timely-happy spirits indu'th. (a)
Yet be it less or more, or soon or slow, (c)
It shall be still in strictest measure even (d)
To that same lot, however mean or high, (e)
Toward which Time leads me, and the will of Heaven. (d)
All is, if I have grace to use it so, (c)
As ever in my great Task-master's eye. (e)
The English (or Shakespearian) Sonnet
The major features:
It is comprised of three quatrains and a final couplet in iambic
Rhyme scheme: abab cdcd efef gg.
Often, the beginning of the third quatrain marks the "turn", or the line in which the poem's mood shifts and the poet expresses a revelation or epiphany.
This example, Shakespeare's Sonnet 116, illustrates the form:
Let me not to the marriage of true minds
Admit impediments. Love is not love
Which alters when it alteration finds,
Or bends with the remover to remove.
O no, it is an ever fixed mark
That looks on tempests and is never shaken;
It is the star to every wandering bark,
Whose worth's unknown although his height be taken.
Love's not time's fool, though rosy lips and cheeks
Within his bending sickle's compass come;
Love alters not with his brief hours and weeks,
But bears it out even to the edge of doom.
If this be error and upon me proved,
I never writ, nor no man ever loved.
The sonnet was introduced into English by Thomas Wyatt in the early 16th
century. His sonnets and those of his contemporary the Earl of Surrey were
chiefly translations from the Italian of Petrarch and the French of Ronsard
and others. Sir Philip Sidney's sequence Astrophel and Stella (1591) started
a tremendous vogue for sonnet sequences: the next two decades saw sonnet sequences
by William Shakespeare, Edmund Spenser, Michael Drayton, Samuel Daniel, Fulke
Greville, William Drummond of Hawthornden, and many others.These sonnets were
all essentially inspired by the Petrarchan tradition, and generally treat
of the poet's love for some woman; the exception is Shakespeare's sequence.
In the 17th century, the sonnet was adapted to other purposes, with John Donne
and George Herbert writing religious sonnets, and John Milton using the sonnet
as a general meditative poem. Both the Shakespearean and Petrarchan rhyme
schemes were popular throughout this period, as well as many variants.
The fashion for the sonnet went out with the Restoration, and hardly any sonnets were written between 1670 and Wordsworth's time.
three quatrains and a final rhyming couplet in iambic pentameter
rhyme scheme: abab bcbc cdcd ee.
In a Spenserian sonnet there does not appear to be a requirement that the initial octet sets up a problem which the closing sestet answers as is the case with a Shakespearean sonnet. Instead, the form is treated as three quatrains connected by the interlocking rhyme scheme and followed by a couplet. The linked rhymes of his quatrains suggest the linked rhymes of such Italian forms as terza rima.
This example, Sonnet 1 from Spencer's Amoretti, illustrates the form:
Happy ye leaves! when as those lily hands,
Which hold my life in their dead doing might,
Shall handle you, and hold in love's soft bands,
Like captives trembling at the victor's sight.
And happy lines! on which, with starry light,
Those lamping eyes will deign sometimes to look,
And read the sorrows of my dying sprite,
Written with tears in heart's close bleeding book.
And happy rhymes! bathed in the sacred brook
Of Helicon, whence she derived is,
When ye behold that angel's blessed look,
My soul's long lacked food, my heaven's bliss.
Leaves, lines, and rhymes seek her to please alone,
Whom if ye please, I care for other none.
The curtal sonnet is a form invented by Gerard Manley Hopkins, and used in three of his poems.
It is an eleven-line (or, more accurately, ten-and-a-half-line) sonnet, but rather than the first eleven lines of a standard sonnet it consists of precisely ¾ of the structure of a Petrarchan sonnet shrunk proportionally, so that the octave of a sonnet becomes a sestet and the sestet a quatrain plus an additional "tail piece." "Pied Beauty" is an example.