From Cyclopaedia: or, an Universal Dictionary of Arts and Sciences by Ephraim Chambers (1783)

Sonnet, Sonetto, in Poetry, a kind of composition properly contained in fourteen verses; viz. two stanzas, or measures, of four verses each, and two of three; the eight first verses being all in two rhymes. The sonnet is of Italian origin, and Petrarch is allowed to be the father of it: it is held the most difficult and artful of all poetical compositions, as requiring the utmost accuracy and exactness. It is to end with some pretty ingenious thought: the close must be particularly beautiful, or the sonnet is defective. . . Of twenty-three sonnets which were written by our great poet Milton, that addressed to Henry Lawes is one of the best; and yet this shews how difficult and unnatural the construction of this species of poem is in the English language; whereas, from the great number of similar terminations in the Italian tongue, and the success of Petrarch, it has long been the favourite measure of Italy for short compositions. . .