Walter Howell Deverell (1827 – 1854) wasn't a member of the PRB but was friends and closely associated with them. It was Deverell who discovered Lizzie Siddal in the draper's shop where she worked and she is in this picture on the left as Viola. Rossetti was the model for the clown. Orsino was a self-portrait by the artist.
He never actually got to join the PRB and died at the early age of 21 of Bright's disease.
It was Mrs Deverell who visited the Siddal's to persuade them that it was okay for Lizzie to model for her son (artist's models were often regarded as or were actually prostitutes at the time). Oddly the Siddal's were related to the Hill's who had a daughter already modelling for Ford Madox Brown (Rossetti's tutor) and was engaged to him. Deverell was very handsome and from a respectable family and this may have been part of the attraction for the family and Lizzie.