We first come across flies painted to demonstrate the skilled craftsmanship of the artist in the works of Giovanni dei Grassi and the Limbourg brothers. The first such example I know of in a panel painting is in the painting of the Death of the Virgin, from the circle of the Master of the Albert altar (Esztergom, Christian Museum). Inspired by Pliny's anecdotes, painting apprentices in Francesco Squarcione's workshop in Padua in the 1460s, especially Giorgio Schiavone, painted trompe l'oeil flies to trick their fellow artists. Among others, humour, the romantic desire to revive antiquity, and the Aristotelian paradox that the ugly in art becomes beautiful also played a role. It was in this environment that Filarete's anecdote in which Giotto fools Cimabue with a painted fly was first concocted. The anecdote is told in the context of the paragone. Trompe l'oeil flies and the glorification of painting are similarly joined in Derick Baegert's painting of St Luke. The fly seen in Dürer's Feast of the Rosegarlands is related both to Dürer's self-portrait in the same painting and to the Opus quinque dierum. Anecdotes about flies so true-to-life as to deceive the viewer to this day survive in newer and newer versions, although the essence of these tales remains the same: the flies demonstrate the artist's humour and his ability to imitate nature.