The English sonnet is also known as a Shakespearean sonnet after its most famous writer. The English sonnet is constructed of three quatrains of alternating rhyme ("abab cdcd efef"), followed by a single couplet. While Shakespeare often placed the sonnet's volta in the ninth line, the English sonnet is flexible about the volta's placement and the form doesn't require its placement in a specific line.
The Italian or Petrarchan sonnet is the original and least flexible of the various types. An Italian sonnet consists of two sections. The first part is an octave, or eight lines, with an "abba abba" rhyming pattern. The second part is a sestet, or six lines. The rhyming pattern for the sestet is somewhat more flexible, although an Italian sonnet never ends with a couplet. The Italian ("cdc cdc") and Sicilian ("cdc dcd") are the two most popular rhyming patterns for the closing sestet. An Italian sonnet's volta is always in the ninth line.
This sonnet consists of three Sicilian quatrains and a final couplet. The rhyming scheme ("abab bcbc cdcd ee") connects each of the quatrains so that they form one unit, although each quatrain introduces a specific thought. Edmund Spenser created this sonnet by experimenting with the rhyming and stanza pattern he used in "The Faerie Queene."