Luini was one of the most famous artists of the Milan school of painting, a follower of Leonardo da Vinci. He repeated Leonardo's favourite themes and types, making virtuoso use of sfumato, the soft misty chiaroscuro which seems to surround objects. The colouring of this picture is deep and calm brown and golden tones emphasizing the dense noble crimson colour of the saint's clothing. At her sides are two small angels holding palm branches, the attributes of martyrdom, and a spiked wheel on which, according to legend, Roman Emperor Maximinus ordered to torture St Catherine for her loyalty to the Christian faith .