The dating of the picture is uncertain. It may have been painted during Millais's long stay in and around Oxford during the summer and autumn of 1850, when he was working primarily on The Woodman's Daughter and Mariana. Millais stayed with the Wyatts at the beginning of this visit, in June, later moving to Botley before returning to stay with the Coombe family in Oxford in September. He did not return to London until November. Sarah Wyatt was born on 17 January 1849 and would have been about twenty months old by the autumn of the following year. There are, however, notes in the possession of the sitters' descendants, probably made early in the present century by a son or nephew of Sarah, which give 1853 as the date of the work. The evidence for this date is unknown and there is no record of Millais visiting the Wyatts in Oxford that year. Judging from the child's apparent age, a date of 1850 is more likely.
On the wall behind the sitters are, from left to right, prints after Raphael's Madonna della Sedia, Leonardo's The Last Supper and Raphael's Alba Madonna. Millais disdained Raphael at this time, and used this portrait to set out his position as a Pre-Raphaelite. His stark, realistic portrayal of this mother and child contrasts sharply with Raphael's soft, idealised depiction of the subject. When hung next to its companion portrait James Wyatt and his Grand-daughter, this work invites comparison with a very different sort of portrait of Eliza Wyatt by Sir William Boxall, a romantic depiction in a circular format, shown hanging on the wall at the top right of the portrait of Mr Wyatt.
Leslie Parris (ed.), The Pre-Raphaelites, exhibition catalogue, Tate Gallery, London 1984, reprinted 1994, pp.81-2, reproduced
The Tate Gallery 1984-86: Illustrated Catalogue of Acquisitions, London 1988, pp.75-6, reproduced