Copies of Inferno and Purgatorio were already circulating in northern Italy when Dante died in September 1321, and these lost early exemplars were the forerunners of hundreds of fourteenth-century manuscripts of the Commedia, complete and partial. Few vernacular texts achieved so rapid or widespread a diffusion anywhere in medieval Europe. But Dante's poem was not long allowed to go about unaccompanied. By 1322 commentators were working on Inferno; by the decade's end a commentary on the whole Commedia had appeared, and the first century of Dante criticism eventually yielded a vast crop of exegesis. It includes full-scale commentaries, in which theoretical prologues, proems to each canto and textual glosses are combined to form an organic whole; sets of individual glosses (chiose), either discontinuous or in connected prose; and a variety of paraphrases, summaries, introductions, biographies, and other prolegomena, frequently in verse, which flourished on the margins of commentary proper, especially in the 1320s. New material continues to come to light: a long-lost Neapolitan commentary on Inferno, of 1369–73, was published in 1998. Commentators wrote in Italian and Latin, all over Italy (Naples, Milan, Bologna, Venice, Verona, Pisa) and abroad (Germany). Even Dante's loved and hated native city paid tribute to the poem that so ruthlessly dissects it: Giovanni Boccaccio and Filippo Villani lectured and wrote on Inferno in Florence, while the Ottimo commento and the work ascribed to the ‘Anonimo Fiorentino’ almost certainly originated there.