Prince William of Prussia is depicted by Hähnisch aged one year, wearing a white lace dress with blue sash and shoulder ribbons and matching lace bonnet, holding a silver rattle in his right hand, a toy figure of Punch lying beside him.The miniature is unusual in showing the Prince's withered left arm, which had been damaged as a result of a birth injury.

On 30 December 1859 Victoria, Princess Royal, wrote to Queen Victoria: 'Hähnisch is painting my miniature and Baby's – … Baby's is quite horrid, too dreadful, so affected and disagreeable, not the least like the child; but he paints quite beautifully only he uses too much violet lilac and pink in the face, not the pure, transparent freshness of Sir William Ross' (RA VIC/Z 9/11). By 11 February 1860 she was able to report from Berlin: 'Hähnisch is copying Baby's Picture for you, and I hope you will have it soon' (RA VIC/Z 9/30). The Princess evidently valued his finished work as she wrote some months later: 'he paints very well you know' (RA VIC/Z 10/10). Queen Victoria's first impressions, on seeing him in Coburg in September, was of 'a fine fat child, with a beautiful white soft skin. We felt so happy to see him at last' (RA QVJ: 25 September 1860).