Little is known about the poet's activity in the immediately succeeding years, and there is no documentation of Dante's official position regarding the events of 1297, when Pope Boniface VIII proclaimed the crusade against the powerful, anti-papal Roman Colonna family and sent Cardinal Matteo d'Acquasparta to Florence to solicit help. But an episode about Guido da Montefeltro in the Inferno clearly expressed the poet's opinion about the "arrogant fever" of Boniface's thirst for power, which led to the stirring up of open conflict between the two Guelf factions of the city, the Black Guelfs (headed by the Donati family, of magnate ancestry) and the more moderate White Guelfs (headed by the Cerchi, a family of bankers and merchants). Donati support of the Pope transformed what had until then been a struggle between municipal parties into a conflict between the commune and the papacy. The signoria of the White Guelf party struck hard against the Blacks, sending them into exile. Boniface sent Cardinal Matteo d'Acquasparta to Florence a second time, in 1300, ostensibly to reconcile the parties but secretly to favour the Blacks. On May 7 Dante was nominated ambassador to San Gimignano to consolidate the Guelf League, then supporting the Pope in a war against the Aldobrandeschi family of Santa Fiora. He was elected one of the six priors, or presidents, of the guilds for the period June 15-August 14, 1300, during which time he and his colleagues gave proof of their impartiality, exiling the heads of both parties; among the latter was Guido Cavalcanti, his "first friend," exiled to Sarzana. But events followed close one upon another: during the succeeding priorate (to which Dante no longer belonged) the signoria government under the Whites recalled their followers from exile, while the Blacks assembled in the spring of 1301 in the church of Sta. Trinita to make another bid to recover power. These were the last months of Dante's political and civic activity: surviving documents present him as the leader of a large group of Whites; and the role that he played in Florentine events between 1300 and 1301, especially after his priorship, cannot be minimized. On September 13,1301, and then again on the 20th and 28th of the same month, he urged that full powers be given to the priorate, in view of the dangers threatening the city.