Don Juan is a satiric poem by Lord Byron, based on the legend of Don Juan, which Byron reverses, portraying Juan not as a womanizer but as someone easily seduced by women. It is a variation on the epic form. Byron himself called it an "Epic Satire" (Don Juan, c. xv, v. 790). Modern critics generally consider it Byron's masterpiece, with a total of over sixteen thousand individual lines of verse. Byron completed 16 cantos, leaving an unfinished 17th canto before his death in 1824. Byron claimed he had no ideas in his mind as to what would happen in subsequent cantos as he wrote his work.
When the first two cantos were published anonymously in 1819, the poem was criticized for its 'immoral content', though it was also immensely popular. (wikipedia.org)