The subject of this important work occurs in Chaucer's 'Legend of Good Women', though Burne-Jones also significantly sites Ovid's 'Heroides'. Phyllis, Queen of Thrace, falls in love with Demophoon, son of Theseus. He departs but promises to return in six months' time. When he fails to keep his promise, Phyllis hangs herself, and is turned by the gods into an almond tree. On his eventual return, Demophoon remorsefully embraces the tree, which blooms, as Phyllis emerges to forgive and reclaim her faithless lover.
Both Phyllis and Demophoon are modelled on Maria Zambaco, with whom Burne-Jones had been having an affair since June 1868 (a host of studies exist for both figures, in various locales). And for this reason, in conjunction with Demophoon's nudity, a controversy ensued when it was exhibited at the Old Watercolour Society for the Summer Exhibition of 1870. Within two weeks of the exhibition's opening, Burne-Jones withdrew the painting due to complaints, and two works by other artists were exhibited in its place. In August 1870, Burne-Jones resigned from the Society, over artistic integrity.
In the catalogue for the Summer Exhibition at the Old Watercolour Society, Burne-Jones included the following caption, a quote from Ovid: 'Dic mihi quid feci? Nisi non sapienter amavi' [Tell me what I have done? I loved unwisely.] Burne-Jones later reworked the painting entirely in oils, transforming the bodies of both Phyllis and Demophoon into an homage to Michelangelo, calling it 'The Tree of Forgiveness' (1882, Lady Lever Art Gallery, Port Sunlight), where Zambaco's face remains only on Phyllis.