Late 1930s or early 1940s.
David Copperfield is the first of Dickens's books that I listened to rather than read, and I found that 33 hours of the audiobook was a great distraction from the endless dark days of winter.
Betsy Trotwood is one of my favorite of all of Dickens' characters, so I was intrigued to find this pattern for Betsy Trotwood (but Dickens spells it Betsey.)
My provisional date of late 1930s is based in part on the design of the envelope and the illustration, but I also wonder if the 1935 film adaptation by George Cukor (starring Freddy Bartholomew as David and W.C. Fields as Mr. Micawber) spawned an interest in David Copperfield-themed fancy dress in the years following the release. I haven't been able to find evidence of a stage adaptation that might also have triggered Copperfield-mania.
Serial publication of David Copperfield started in 1849, but when does take place? If you assume that it's partially auto-biographical, that sets the novel in the 1820s through the 1830s. I think that this is an awkward period for women's clothing, with the long sloping shoulder line leading to enormous sleeves - a difficult look for even a very well-proportioned woman to wear successfully.
Edna May Oliver played Aunt Betsey in the 1935 film, and Dolly Tree, the costume designer, seems to borrow from the 1830s for the exuberant cap.
|Image from oldhollywoodfilms.com|
Weldon's Betsy Trotwood carries a garden hod and trowel, a visual cue that this vaguely 19th century lady is the Aunt Betsy that David Copperfield surprised as she was working in her garden.
This unprinted pattern does not appear to have been used, though it is water stained.