There's a whole section on Liberty's "costumes", written by Judith Watt, in Stephen Calloway's "Liberty of London. Masters of Style and Decoration" (which I just got earlier this week!). A few excerpts:
"From its opening in 1884, Liberty's Costume Department maintained its sartorial identity, uninfluenced by the couturiers of Paris. Visitors to the department would select a style of costume, which was then run up in the workrooms in Liberty fabric. From 1894, catalogues for mail order were introduced, with sections for gowns, mantles and millinery, ranging from historically based costumes to the more conventional...
"E. W. Godwin, the architect and aesthete appointed by Liberty to run the department from its beginning, believed it was possible to adapt historical prototypes to current dress without making the end result either 'eccentric or bizarre'. The art fabrics were indeed sometimes difficult to work with, but a skilled in-house dressmaker could usually do any job quickly...
"By 1890, Liberty catalogues were featuring different historical styles adapted for the day. 'Athene' was a gown in 'Arabian cotton with silk Himation' for four and a half guineas; the waist is unconstricted by a corset. Other styles on offer were 'Greta', with artistic smocking and medieval embroidery, 'Marianne,' with flowing lines in cashmere and brocade for nine guineas or Venetian silk and velvet for eighteen guineas. 'Valeria' has a medieval flavour with embroidery at the neck, and, as recommended by the Rational Dress Society, the weight falls from the shoulders, not the waist."
Your gown is amazing, and I look forward to learning more about it!