Sonnet
It was, however, Sir Philip Sidney's sequence "Astrophel and Stella" (1591) that started the English 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, with the exception of Shakespeare's sequence of 154 sonnets. The form is often named after Shakespeare, not because he was the first to write in this form but because he became its most famous practitioner. The form consists of fourteen lines structured as three quatrains and a couplet. The third quatrain generally introduces an unexpected sharp thematic or imagistic "turn", the volta. In Shakespeare's sonnets, however, the volta usually comes in the couplet, and usually summarizes the theme of the poem or introduces a fresh new look at the theme. With only a rare exception (for example, Shakespeare's Sonnet 145 in iambic tetrameter), the meter is iambic pentameter.
Shakespeare's sonnets
The title of the quarto, "Shakespeare’s Sonnets", is consistent with the entry in the Stationer Register. The title appears in upper case lettering on the title page, where it is followed by the phrase “Neuer before Imprinted”. The title also appears every time the quarto is opened. That the author’s name in a possessive form is part of the title sets it apart from all other sonnet collections of the time, except for one — Sir Philip Sidney’s posthumous 1591 publication that is titled, "Syr. P.S. his Astrophel and Stella", which is considered one of Shakespeare’s most important models. Sidney’s title may have inspired Shakespeare, particularly if the “W.H.” of Shakespeare’s dedication is Sidney’s nephew and heir, William Herbert. The idea that the persona referred to as the speaker of the Shakespeare’s sonnets might be Shakespeare himself, is aggressively repudiated by scholars, however, the title of the quarto does seem to encourage that kind of speculation.