Commentary Par XVI 94-99

Carroll: '[These lines] refer to the Cerchi (see DDP Carroll.Par.XVI.58- 66]).  Their houses were above the Porta San Piero, and had been acquired by this wealthy family from the Conti

Guidi, who sprang from the ancient house of the Ravignani, the head of which was the Bellincion Berti of [Par XV 112].  The fellonia or treason charged against the Cerchi seems to be their failure as leaders of the Whites to defend the city against the Blacks in Nov. 1301.  Dino Compagni says "their hearts failed them through cowardice": the Priors gave them orders to prepare for defense and urged them "to play the man."  But "from avarice" they refused to pay the hired troops, made practically no preparations, and so handed over the city to six terrible days of outrage and pillage.  The exile of the Whites which followed is the "lightening of the barque" to which Dante refers in line 96.  For a full account of this disastrous struggle between the Bianchi and the Neri, see Dino Compagni's Chronicle, Bk. II, and Villani's, VIII.38-49.'

These six lines have been the cause of a certain confusion and of considerable debate; Carroll's view, however, seems sensible.  For an English translation of Dino Compagni's chronicles of Florence in Dante's time, written by one of his contemporaries, see Compagni (Comp.1986.1).