Beginning with several tales in Giovanni Boccaccio’s Decameron, the early fourteenth-century Florentine painter Buonamico Buffalmacco was often portrayed as a carefree, funloving trickster. As this paper demonstrates, that image has obscured the deeper significance that Buffalmacco and his works held for Giorgio Vasari in the second edition of The Lives of the Artists (1568). That significance is especially apparent in his account of the eccentric painter and his dealings with the nuns of Faenza. In two humorous anecdotes about the nuns and Buffalmacco, Vasari poetically reveals the aesthetic and theological significance of the painter’s art. In spite of Buffalmacco’s less-than-diligent character, Vasari praises his ability to “transubstantiate” paint, an ability that placed him among the primi lumi.