For several decades, a small number of scholars have denied the attribution of the tenzone with Forese Donati to Dante. Early in the twentieth century, Domenico Guerri argued that some poet of the late Trecento or first decade of the Quattrocento wrote it (1). More recently, Antonio Lanza and Mauro Cursietti asserted that the author might have been Stefano Finiguerri, nicknamed "il Za. (2)" Those scholars propose that the six sonnets of the tenzone were actually part of an elaborate hoax. The singular author, they claim, wrote them to slander a homosexual couple living in Florence at that time. That poet, the scholars assert, decided to call the two men "Dante" and "Forese" because of the homoerotic overtones of Purgatorio 24. Yet the argument that Finiguerri or another poet of the late Trecento or early Quattrocento authored the poems is quite controversial. I propose that other evidence exists that relates to the validity of such a theory. I hold that other information strengthens the position held by the majority of dantisti that the tenzone was indeed composed during the late Duecento.
For some time scholarship has noted the intertextuality between Dante's first sonnet in the tenzone, "Chi udisse tossir la mal fatata," and a sonnet by Rustico Filippi, "Io fo ben boto a Dio: se Ghigo fosse. (3)" In his sonnet, Dante claims that Forese's wife suffers from extreme cold, implying that her husband ignores her sexually. She coughs and shivers even in the middle of August:
Chi udisse tossir la mal fatataRustico says much the same about Ghigo, a man whose wife is unfaithful. He too is freezing, even during the month of July, and has a hacking cough:
[...] per pillicion di quella c'ha le fosse,The similarity is so strong between the two poems that it does not appear to be coincidental. Rather, it seems that Dante deliberately recalls Rustico. The intertextuality suggests that he had intimate knowledge of Rustico Filippi's poetry. Therefore, the renown that Rustico enjoyed, both while alive and posthumously, bears directly on the question of the ascription of the tenzone with Forese Donati.
The documents that attest to Rustico Filippi's literary impact appear to follow a general pattern regarding their dating. Brunetto Latini dedicates the Favolello to Rustico Filippi in the 1260s. Fifty-eight of Rustico's fifty-nine sonnets appear in the manuscript Vaticano Latino 3793; of those, fifty-six are unici texts, including "Io fo ben boto a Dio: se Ghigo fosse." That codex was most likely compiled during the 1290s (4). The poet Iacopo da Lèona satirizes Rustico in the sonnet "Segnori, udite strano malificio," and Iacopo's sonnet also appears only in Vaticano Latino 3793 (5). Only three of Rustico's sonnets are found outside the Vaticano Latino 3793 codex. One of them, "Due cavalier valenti d'un paraggio," the opening of a two-sonnet tenzone with Bondie Dietaiuti, is found in three other manuscripts: Chigiano L. VIII. 305 (mid-fourteenth century) (6), Marciano IX It. 529 (early fourteenth century) (7), and Magliabechiano VII 1040 (fourteenth century) (8). Moreover, in the commentary to Francesco da Barberino's Documenti d'amore, Rustico is mentioned as a vituperator of women. Francesco's poem is believed to have been completed by the year 1316 (9). Thus, virtually all the documents which mention Rustico or contain his works were composed during his lifetime or during the decades immediately following his death.
The information about Rustico's fame is not unequivocal, however, because two sonnets are found in manuscripts of later centuries. The only lyric by Rustico not also included in Vaticano Latino 3793, "Vogliendo contentarla di composte," appears in a manuscript of the Quattrocento, Vaticano Urbinate 697 (10). That manuscript contains a rubric which spells out the lyric's author as "Rustico barbuto." The other poem, "I' agio inteso che sanza lo core," was transcribed into Vaticano Latino 3214 by Pietro Bembo in 1523 (11). A broad conclusion about Rustico's fame and posthumous reputation can be drawn from the documentation: Rustico was renowned among readership during the latter half of the thirteenth century and the first half of the fourteenth century. After that period, some references to Rustico may be found from time to time, but they are highly sporadic in the extant manuscripts. Judging from the evidence, we can say that after the 1350s at the latest, the public as a rule no longer seems interested in Rustico or his poetry. The indications of Rustico's literary impact suggest that his fame was sudden and widespread but did not endure. He gained much attention during his age and immediately thereafter, but after several decades he seems to have been forgotten by the literati.
The above picture of Rustico's reputation does not disprove the theory that a poet of the late Trecento or early Quattrocento could have composed the tenzone. After all, that Bembo transcribed one of Rustico's sonnets in the sixteenth century demonstrates that someone like Stefano Finiguerri could have imitated him in the late Trecento. The dating of Rustico's fame to roughly 1260-1350, however, makes the hypothesis less probable. It would mean that "il Za" knew about the singular exemplar of Rustico's poem at a time when Rustico was all but forgotten. More importantly, if the correspondence was written in the last decade of the fourteenth century, as those scholars argue, then the recollection of Rustico seems unmotivated. It would not follow that the poet would deliberately echo a versifier whose fame was already eclipsed. As the evidence demonstrates, during the 1390s Finiguerri could not reasonably hold the expectation that the readers would notice the stylistic connection to Rustico; by that time, the documentation shows, Filippi had already faded from the collective memory. In contrast, from the perspective that Dante truly participated in the tenzone the intertextuality with Rustico does not appear incongruous in the slightest. Since the tenzone speaks of Dante's father being already dead, it must have been composed at some time between the year of the death of Dante's father, 1283, and the year of Forese's death, 1296 (12). The dating of the tenzone to the 1280s and 1290s corresponds with the height of Rustico's renown. Thus, it takes no effort to explain how Dante had familiarity with the fellow Florentine Rustico Filippi. Moreover, it would follow logically that the young Dante might paraphrase Rustico because Dante could expect the readers to note the reminiscence of Filippi's sonnet about marital infidelity. He could utilize the intertextuality to underscore his own slander of Donati's sexual prowess. In conclusion, the information about Rustico's reputation does not contradict outright the theory about "il Za" as the author of the tenzone. It does, however, further reinforce the opinion that Dante and Forese actually authored the slanderous verse to one another during the latter decades of the Duecento.
 Domenico Guerri, La corrente popolare nel Rinascimento (Firenze: Sansoni, 1931). Guerri's four articles on the subject are currently collected in Scritti danteschi e d'altra letteratura antica (Roma: De Rubeis, 1990).
 Antonio Lanza "Una volgare lite nella Firenze del primo quattrocento: la cosiddetta tenzone di Dante con Forese Donati--nuovi contributi alla tesi di Domenico Guerri" in Polemiche e berte letterarie nella Firenze del primo quattrocento (Roma: Bulzoni, 1971): 396-409. Mauro Cursietti, La falsa tenzone di Dante con Forese Donati (Roma: De Rubeis, 1995).
 Mario Marti, ed., I poeti giocosi del tempo di Dante (Milano: Rizzoli, 1956): 50; Maurizio Vitale, ed., Rimatori comico-realistici del Due e Trecento (Torino: UTET, 1965): 147; Pier Vincenzo Mengaldo, ed., Rustico di Filippo: Sonetti (Torino: Einaudi, 1971): 56; Franco Manca, "Dante e la poesia realistico-borghese" Canadian Journal of Italian Studies 8: 30 (1985): 33-34; Giuseppe Marrani, "I sonetti di Rustico Filippi" Studi di filologia italiana 57 (1999): 156
 Domenico de Robertis, "Censimento dei manoscritti di rime di Dante (I)," Studi danteschi 37 (1960): 211-212. The manuscript itself is dated between the fourteenth and sixteenth centuries, but the sonnet in question appears in the section written in the Trecento.