La Belle Iseult (formerly known as Queen Guenevere)

"This is the only completed easel painting that William Morris produced. It is a portrait in medieval dress of Jane Burden, whom Morris married in April 1859. The picture has been identified in the past as Queen Guenevere, partly owing to the fact that Morris published his first volume of poetry, The Defence of Guenevere, in March 1858. However, recent research has established convincingly that the picture is intended to represent Iseult mourning Tristram's exile from the court of King Mark."

— "La Belle Iseult" on tate.org.uk