Niccolò di Raffaello di Niccolò dei Pericoli, called "Il Tribolo" (1500–7 September 1550) was an Italian Mannerist artist in the service of Cosimo I de' Medici in his natal city of Florence.
Niccolò di Raffaello began as an apprentice to a woodcarver but, while still in his teens, was taken up as an assistant by Andrea Sansovino. Giorgio Vasari, in his Vite, mentioned numerous early figures and fountains by Tribolo that can no longer be traced.
A court artist like his successor Bernardo Buontalenti, he was expected to function well as a member of a team; like Buontalenti's, his name has been overshadowed by greater personalities. For example, in the 17th and 18th centuries, connoisseurs attributed to Michelangelo some of Tribolo's drawings for sculptural niches and wall fountains, a tribute to Tribolo's bravura as a draughtsman and a sign of Michelangelo's influence on his style.
From 1517 he had returned from Venice to Florence, working on his own. In his autobiography, Benvenuto Cellini tells of his trip to Venice with "Tribolino" for whose son he had stood godfather. In Bologna, where they saw some Florentine exiles at an inn, the cautious Tribolo, "the most timorous man that I have ever known, kept on saying: 'Do not look at them or talk to them, if you care to go back to Florence'" In Venice, after several days' journey, it soon appeared that Jacopo Sansovino had no present work for Niccolò, but invited him to drop in again, at his convenience.
Vasari tells of the painter Giuliano Bugiardini who had been at a loss to draw a file of figures and "foreshorten them so that they should appear all in a row, or how he could find room for them in so narrow a place. Buonarroti, feeling compassion for the poor man, took up a piece of charcoal and sketched a file of naked figures with all the judgment and excellence proper to him, and went away with many thanks from Giuliano. Not long after, the latter brought Il Tribolo his friend to see what Buonarroti had done, and told him all about it; but because Buonarroti had only sketched them in outline, without any shadow, Bugiardini could not carry them out; so Il Tribolo resolved to help him, and he made some rough models in clay, giving them all that rough force which Michelangelo had put into the drawing; and so he brought them to Giuliano. But this manner did not please Bugiardini's smooth fancy, and as soon as Il Tribolo was gone he took a brush and, dipping it in water, smoothed them all down. Il Tribolo, hearing about it from Giuliano himself, laughed at his honest simplicity, and the work was at last finished, so that none would have known that Michael Angelo had ever looked at it."