Sara Prinsep, née Pattle, was the third of the seven Pattle sisters who played such a significant role in the annals of Victorian art. Her elder sister was the celebrated photographer Julia Margaret Cameron. Sara married Henry Thoby Prinsep, an Indian civil servant, and in the 1850s and 1860s held a salon at their London home, Little Holland House, Kensington. This was frequented by a star-studded group of writers and artists, including Carlyle, Tennyson, Thackeray, Dickens, Rossetti, Burne-Jones and Browning.
Watts was her 'resident genius', having various studios within the house and grounds. He painted many portraits of the family and their distinguished guests, while Sara and her sisters attended to his every need. Watts and the Prinseps remained at Little Holland House until the house was demolished in 1874.
For further information see W. Blunt, England's Michelangelo, A Biography of George Frederick Watts, London, 1975, p. 77.