Oliver Goldsmith
Lord Byron to John Murray 23 April 1820; Letters and Journals, ed. Rowland E. Prothero (1898-1901) 5:18.
You say that one half [of Don Juan] is good: your are wrong; for, if it were, it would be the finest poem in existence. Where is the poetry of which one half is good? is it the Aeneid? is it Milton's? Is it Dryden's? is it any one's except Pope's and Goldsmith's, of which all is good? and yet these two last are the poets your pond poets would explode.