In this 1556 self-portrait, Sofonisba shows herself in the act of painting, applying mixed pigments to a canvas that depicts the Virgin and Christ Child tenderly kissing. She gazes outward—as if we have just interrupted her in mid-stroke. Her expression is calm and reserved. A maulstick (a common device used to support the artist’s hand) held in her left hand supports her right hand as she touches the brush to the canvas.
The inclusion of a painting of the Virgin Mary and Christ child in the 1556 self-portrait further reflects on Sofonisba’s virginity. While Mary feeding, kissing, or embracing Christ as a child were common subjects of this era, it is likely that Sofonisba incorporated this intimate scene between mother and son here to fashion herself as a virtuous woman—one who identifies with the ultimate virtuous woman, the Virgin Mary.
(https://smarthistory.org/sofonisba-anguissola/)