The Revolt of the Ciompi was a peasant revolt in late medieval Italy by wool carders known as ciompi.
A typical embroglio among factions within the grassi (the "well-to-do")= fat, grassi is plural sparked the uprising. Members of the lower classes, called upon to take part in late June, 1378, took matters into their own hands in July. They presented a series of petitions to the governing body, the Signoria, demanding more equitable fiscal policies and the precious right to establish guilds for those groups not already organized. Then, on July 22, the lower classes forcibly took over the government, placing the wool carder Michele di Lando in the executive office of gonfaloniere of justice, and showing their banner at the Palazzo della Signoria.
The revolutionaries within the Florentine republic were backed by radical members of the usually powerless minor guilds, the arti minori. They extended guild privileges to the ciompi, and for the first time a European government, however briefly, represented all the classes of society.
But the ciompi were disillusioned within a matter of weeks that summer, when the new government failed to implement all their utopian demands. Conflicts of interests between the minor guilds and the ciompi became evident. On August 31 a large group of the ciompi that had gathered in the Piazza della Signoria was easily routed by the combined forces of the major and minor guilds. In reaction to this revolutionary episode, the new ciompi guild was abolished, and within four years the dominance of the major guilds was restored.
Niccolò Machiavelli's Florentine Histories depicts the revolt with a series of invented debates and speeches that reflect the positions of the protagonists, seen from the point-of-view of a later champion of state stability.
After the Black Death, similar upheavals in the second half of the 14th century, in which the most downtrodden classes struck out for fairer conditions, widely disturbed European polities and were looked on by the Church and governing classes as reversals of God's natural order. Compare Wat Tyler's rebellion of 1381 in England and the Jacquerie of 1358 in France. See also popular revolt in late medieval Europe.