Giovanni Antonio Boltraffio

Milan in the 1490s was Leonardo da Vinci's city, and around him gathered a workshop of young painters trying to learn what he knew. Giovanni Antonio Boltraffio was the odd one among them. He came from a well-off Milanese family, the kind of background that usually pointed a young man toward law or the church rather than the messy trade of paint, and he took up the brush anyway, training directly under Leonardo.

He became one of the two most gifted painters to come out of that circle, alongside Bernardino Luini, a fellow pupil. You can see the lesson and its limit in his portraits, often shown in strict profile: the modelling is soft and careful, learned from Leonardo, while the outlines stay clean and hard, without the smoky blur, the sfumato, that made his master's faces seem to breathe.

His masterwork he painted away from Milan. Around 1500 he spent time in Bologna, where the Casio family took him up, and for them he made the large altarpiece now in the Louvre, a Madonna and Child with two kneeling donors, the poet Girolamo Casio and his father. One picture keeps his name in dispute to this day, the Madonna Litta in St Petersburg, a small, tender image long linked to Leonardo himself and still argued over, with many scholars giving the actual painting to Boltraffio's hand.