Commentary Purg V 64

The speaker, never identified by name, either in his own speech of 21 lines ([Purg V 64-84]) or by the narrator, is Jacopo del Cassero, born ca. 1260.  'He was among the Guelf leaders who joined the Florentines in their expedition against Arezzo in 1288.  He incurred the enmity of Azzo VIII of Este by his opposition to the designs of the latter upon Bologna, of which city Jacopo was Podestà in 1296.  In revenge Azzo had him assassinated at Oriaco, between Venice and Padua, while he was on his way (in 1298) to assume the office of Podestà at Milan at the invitation of Maffeo Visconti.  He appears to have gone by sea from Fano to Venice, and thence to have proceeded towards Milan by way of Padua; but while he was still among the lagoons, only about eight miles from Venice, he was waylaid and stabbed' (Cassero, Jacopo del).  Clearly Dante knew that he could count on Jacopo's renown and on his readers' fairly wide acquaintance with the details of his life and death.