A distinguished member of the Guelph aristocracy for more than two decades, Corso Donati was particularly influential in Florentine government. He held numerous positions of leadership both in Florence and in nearby cities. As well as being a skilled politician, Corso was an able military commander, playing a decisive role in Florence's victory over the Ghibelline Arezzo at the Battle of Campaldino in 1289.

Not long after the fall of the anti-aristocratic regime of Giano della Bella in 1293, the Guelph party divided into two rival factions: the "Blacks," headed by the Donati clan and other long-standing noble families, and the "Whites," led by the Cerchi clan and families of more recent prosperity. By 1300 hostilities between the Black and White factions had escalated to frequent bouts of violence within the city. Later that year the two priors of Florence pronounced a sentence of exile upon the leaders of both parties. The exiled Donati sought Pope Boniface's intervention, and convinced him to send Charles of Valois into Florence in 1301, supposedly in order to "pacify" the city. Shortly after Charles' entry, Corso Donati stormed the city with a group of exiled Black Guelphs whose numbers were increased by the recent release of sympathizers from the Florentine prisons. The mob wrested control of the city from their political opponents.

Although the Black Guelphs gained control of Florence as a result of this attack, Corso's brazenness and presumption were deemed excessive even by many members of his own party. By 1304, the faction split as a result of political conflict. In the wake of this internal strife, support for Corso was considerably weakened. Corso Donati was killed by Catalan mercenaries while he was trying to escape arrest in 1308.

In the eighth tale of Day Nine, Corso Donati and Vieri de' Cerchi, heads of the rival Guelph factions, are presented not with reference to their political activities, but as examples of wealthy members of the upper classes ("ricchi erano e di mangiar delle buone cose si dilettavano").

(R.P./N.S.)Adapted from Raveggi, Sergio. s.v. Donati, Corso. Vol. 41. Dizionario biografico degli italiani, Roma: Istituto della Enciclopedia italiana, 1960. pp. 18-24; Toynbee, P. Dictionary of Proper Names and Notable Matters in the Works of Dante. Oxford: Clarendon, 1968. pp. 176-177.