Pier delle Vigne has enjoyed an interestingly mixed press among Dante’s commentators through the centuries, with some respondents feeling empathetic resonance with his apparent generosity of spirit in his faithful service to his earthly lord, while others take a more orthodox hard-line approach to the central fact of his suicidal end. We find both positions taken in a single space in the commentary of John S. Carroll (1904, to vv. 58-78 [DDP]):
Indeed, at first blush Pier may seem to deserve our sympathy, as he has to so many readers, especially in the nineteenth century and into our own era, along with other 'sympathetic' figures. One immediately thinks of other such apparently attractive characters as Francesca, Cavalcante, Brunetto, Ulysses, and Ugolino, all of whom – like Pier – have managed to gain more of the sympathy of even enthusiastically Christian readers of Inferno than the poet might have authorized. Closer examination of their sins and of the nature of their own self-protective rhetoric and selective review of the evidence against them reveals their desire to project a self that is less deserving of punishment and even worthy of sympathy. It is my strong belief that Dante has indeed forestalled any such sympathetic view of Pier's motives and actions by his delicate but nonetheless observable lines of demarcation that reveal the similarities of Pier's behavior to that of Judas Iscariot.
Judas has a fairly frequent presence in Inferno, mentioned at IX.27 in the reference to the "cerchio di Giuda"; referred to obliquely but nonetheless clearly at XIX.96 as "l’anima rea" whose place among the Apostles was not sold to Matthew when he was chosen to replace Judas; and referred to once again a penultimate time (at XXXI.143), before we observe him in his only physical presence in the poem, displayed for eternity, when we finally do see him, in Satan’s central maw (XXXIV.61-63):
This brief notice of the presence of Judas as an alter ego of Pier delle Vigne marks a return to earlier work.
This is hardly the first effort to link Judas to Pier delle Vigne. Pietro di Dante, in the second redaction of his commentary (to Inf. XIII.16-51), citing St. Jerome's comment on Psalm 8, argues that Judas offended God more by hanging himself than by betraying Him to the Romans. Dante's son, however, did not develop the presentation of Judas as the quintessential suicide in the controlling image of this canto. Indeed, some six centuries had rolled by before anyone would refer to Pietro's observation or at least offer some sense that Pier's fealty to his emperor masked a failure of loyalty to his true lord, Jesus Christ. In our own time, perhaps the first to take such a position was Gianvito Resta. A fuller expression of this insight was developed by Anthony Cassell. While Cassell's reading, duly noting Dante's son's previous notice (if not Resta's) of the figure of Judas lurking in the background, mainly involves Pier's betrayal of Frederick, the perhaps better understanding is to allow Pier his proclaimed fealty to his emperor, but to realize that his very words reveal that if his temporal allegiances were respected, they had displaced his only truly significant loyalty, which he owed – at least in a Christian dispensation – to the only essential lord, Jesus Christ. The denial of Christ's authority played a significant role in the behaviors of the emperor whom he served, Frederick II, revealed as punished for heresy a few cantos earlier (Inf. X.119). It is difficult to read Pier's words in any other way: "vi giuro che già mai non ruppi fede / al mio segnor” (XIII.74-75). Even if we allow Pier his claim (and we do not find him punished in the ninth Circle, where such a sin might indeed have located him), a deeper reading of his "oath" should make us see that, like Judas, he did betray his Lord, as Stephany has shown, precisely in his loyalty to the emperor, whom he treats, in his eulogy of Frederick, as being in his own kingly person all the Christ one needed. And thus, in imitation of Judas, Pier will have his body hanging on a tree for eternity. Pier is situated among the suicides. His silence about Christ may tell us more about the nature of his faith – or lack of it – than most readers have until now fathomed. Thus this is an argument ex silentio – Pier has Frederick in his heart where the apparently absent Christ should be, as he himself makes plain: "già mai non ruppi fede / col mio segnor" (Inf. XIII.74-75). No sin is more declarative of a lack of faith in God than suicide. Pier kept his faith with the wrong lord.
 For the programmatic nature of the appearances of these "sympatheic sinners," see my treatment of this subject in "Fear, Pity, and Firmness in Inferno," an appendix to Allegory in Dante's "Commedia" (Princeton: Princeton University Press, 1969), 301-7.
 See the gloss to Inferno XIII.73-75 in my commentary to the Commedia in Robert and Jean Hollander, trans., The Inferno (New York: Anchor Books, 2002), p. 253. That commentary is also available in both the Dartmouth and Princeton Dante Projects.
 See his Dante's Fearful Art of Justice [Toronto: University of Toronto Press, 1984], 46-56. Cassell's title for his volume is misleading; it seems beyond dispute that he clearly meant to say "Fearsome," not "Fearful."
 For further consideration of Frederick, Pier, and of the court life that they shaped and shared, see Christie Fengler and William Stephany, "The Capuan Gate and Pier della Vigna," Dante Studies 99 (1981), 145-57; and Stephany, "Pier della Vigna's Self-fulfilling Prophecies: the 'Eulogy' of Frederick II and Inferno 13," Traditio 38 (1982), 193-212.