The account of the fish-buying detail comes from Vasari, who wrote that Michelangelo counterfeited Schongauer's engraved sheet in pen so exactly that the copy could not be detected, then painted the same design in colour, and went so far as to buy fish with bizarre, scaled colouring purely to help him invent convincing textures for the demons^[1]. Historians studying Vasari's biographical method have noted that this exact narrative pattern, a gifted boy copying an existing image and improving on it through some ingenious extra step, recurs across several of Vasari's artist biographies, including a similar claim about the young Leonardo gathering lizards, snakes and rotting creatures to invent a monster^[4]. That repetition does not mean the Michelangelo story is invented, but it is a documented literary pattern in Vasari's writing rather than a uniquely verified anecdote^[4].

Michelangelo entered the workshop of Domenico Ghirlandaio at fourteen, under a contract his father Lodovico signed on 1 April 1488, committing him to three years' service in exchange for a payment of gold florins to the family^[1]. Ghirlandaio's bottega was, by Michelangelo's own later account, an art factory, turning out panel paintings and frescoes at volume, with apprentices grinding colours and preparing brushes as the entry-level work of the trade^[3]. Both Vasari and Michelangelo's other biographer Condivi agree that the young apprentice's talent was unusually precocious, even as Michelangelo himself, later in life, tried to minimise his debt to this training, preferring to be remembered as a sculptor rather than as a painter who had come up through an ordinary workshop system^[3].

The composition Michelangelo copied was the work of Martin Schongauer, the most accomplished German engraver of the fifteenth century and the first printmaker also known as a painter, working from Colmar in the Upper Rhine^[5]. His Saint Anthony Tormented by Demons, made around 1480 to 1490, shows the saint caught inside a revolving mass of spiky, clawed demons that pull at his scarf and lift him into the air, rendered with unmatched control over tonal variation and surface texture, from smooth skin to scaly hide^[5][6]. Schongauer's design was influential well beyond this one copy; other artists of the period, including apprentices and painters working from prints, used his engravings as models for larger-scale pictures^[5].