Between 1916 and 1920.
Superior was the Sears, Roebuck house brand for sewing patterns, but it's interesting to see this pattern appear in newspapers over several years.
The first reference I've found is in 1916. The artwork is slightly different, but it's definitely the same design and very possibly the same artist.
Buffalo Courier Express for Friday, August 11, 1916, p.7
The style of the illustration makes me think this is from Beauty Pattern Company.
The next year, in 1917, the pattern number had been changed from 947 to 7947, and new illustration was being used - this one exactly like the one on the Sears pattern.
The Nebraska Farmer for Saturday, February 3, 1917, p.12
The pattern was still being advertised in the newspapers in 1920 with its third round of artwork. Here it is in the section "Patterns by Clotilde"
Chicago Tribune, Sunday, May 23, 1920, p. 76.
Clotilde also offers some detailed instructions for making a lining for the yoke to make it stronger. This is more detail than is given on the Sears pattern envelope, a shrewd strategy for giving readers a reason to purchase the Tribune over newspapers that simply listed the pattern and description.
At about the same time, the Woman's Institute of Domestic Arts & Sciences cautions against making maternity wear that "serves to emphasize this condition because of the special, and perhaps unusual features it embodies." The author goes on to recommend developing maternity wear "almost entirely from one kind of material, the contrast being provided merely by a collar..." Lengthwise lines from shoulder to hem are recommended to help draw attention away from the widening mid section.
The designer of this pattern seems to have had much of this advice in mind. This is a thoughtful, practical design that isn't too much different from other apron dresses of the period. Indeed, the 1916 article in the Buffalo Courier states that "...this maternity apron dress in general effect, differs in no way from a dress in the prevailing style for practical wear." The box pleats front and back add needed girth. The elbow length sleeves are ideal for a working garment, and the square neck and contrast trim are an economical, stylish touch. The 1920 pattern illustration does a good job of showing a contrasting button band that emphasizes length over girth.
Although the envelope is rough, the unprinted pattern pieces are in very good condition.
Happy Mothers' Day.
