Shakespeare's Career as a Sonneteer
In all likelihood, Shakespeare wrote the 154 verse pieces that constitute his Sonnets at an early juncture in his career, and after 1598 or so, he abandoned both the sonnet form and the composition of non-dramatic poetry. Shakespeare's motives in engaging in this genre at a time when he had already written several plays was undoubtedly related to a short-lived fad in the court of Queen Elizabeth. In 1591, a year or two before Shakespeare began to write sonnets, Sir Philip Sydney Astrophel and Stella sonnet cycle was first published, and its immediate popularity among Elizabethan aristocrats inaugurated a vogue that many other poets tried to exploit. In short order, Samuel Daniel (Delia, 1592), Michael Drayton (Ideas Mirrour, 1594) and Edmund Spenser (Amoretti, 1595) authored sonnet cycles.
By the time that Shakespeare's Sonnets was published in 1609, however, and probably years before, the enthusiasm of courtly patrons for sonnet cycles had evaporated. By then, Shakespeare had established his renown as a dramatist and dedicated his artistic labor exclusively to the theater. Modern readers may find it surprising that Shakespeare's Sonnets were not popular during the seventeenth or the early eighteenth centuries. The sonnets were not included in the authoritative First Folio of 1623 published after Shakespeare's death. There are very few allusions to Shakespeare having every written sonnets during the century after his death. In fact, the sonnets were not incorporated into Shakespeare's official canon until 1790.
In 1640, a spurious edition of Shakespeare's sonnets was published by John Burton under the title of Poems: Written by Will Shake-speare. Gent.. For the next 140 years, it was Burton's version of the sonnets that was in circulation and treated as the official text. But Burton made some key changes to Shakespeare's original. Rather than 154 verses pieces, Burton's edition lumps together sets of two to five sonnets in synthetic poems that are much longer than their composite originals and, as such, are at total variance from the standard fourteen-line model. This, in itself, strongly suggests that the English court no longer wanted sonnets (or sonnet cycles) but extended verse pieces. Burton eliminated the number sequence from the 1609 version and inserted descriptive titles couched in the generalized third person, such as "Complaint for His Love's Absence." These emendations indicate that tastes had changed dramatically since Shakespeare's time.
Within the sonnets themselves, the narrator gives us cause to believe that the fair youth is his patron. The narrator alternatively expresses confidence in the constancy of the young man's emotional (and financial) support and complains about the efforts of a rival to woo the fair youth's sponsorship. In the early 1590s, Shakespeare himself faced a similar quandary. His career in the theater had not yet reached the stage at which he could rely solely on ticket sales to the public at large for his livelihood. In all probability, it was for the purpose of garnering supplemental funds that Shakespeare wrote his sonnets, essentially cashing in on the popularity of the form among wealthy devotees of the arts. Once this fad had passed, Shakespeare no longer required direct financial assistance. As a prominent playwright and producer, his main source of income was far less vulnerable than the patronage of handful of rich patrons. Commercial considerations probably motivated Shakespeare to take up sonnet writing in the first place; financial independence enabled him to abandon a literary craft with a thin and unpredictable funding base.
There is, however, another reason why the Bard turned his back on the composition of sonnets. Shakespeare's sonnets differ radically from those of his predecessors and his contemporaries. There are no trains of gods or goddesses in his sonnets; Cupid does not make an appearance in these poems; Love, while prominent as a theme, is never personified as a god. Unlike those working in the sonnet tradition, Shakespeare's narrator is not enamored of a proud, chaste lady the very thought of whom inspires divine thoughts. He addresses an inconstant young man and a sexually experienced dark lady, and neither of them inspires contemplation of the divine. Moreover, the introduction of a "rival poet" into the young man cycle (first mentioned in Sonnet #21) has no parallel in the sonnet tradition as Shakespeare inherited it.
Undercutting both Platonic philosophy and Christian belief, Shakespeare's sonnets are representative of a phenomenon that often occurs when a particular artistic form has been worked for centuries, parody. Filled with irony and ambivalence, they can be read as a "lower-case" lampoon of the "high-minded" sonnets that preceded them. If that is the case, Shakespeare's abandonment of the sonnets may have been motivated by his estimation of them as an artificial form that he abused by introducing vulgar elements. Having punctured the balloon of a pompous form once, there was no need for Shakespeare to use the sonnet anew. In other words, changing markets aside, Shakespeare may have stopped writing sonnets because he never took the form seriously in the first place.
I found an interesting statistical approach to finding out when the sonnets were written. Worth a look if you like numbers and stats.
A nice little website discussing some of the major themes of the sonnets.
A good essay on Shakespeare sonnets at this site.