What I have learned ....
Lees Minerva introduced the brand early 1933
This yarn was 100% wool, sold in 4-oz skeins in 40 beautiful colors -- quite a variety of colors for first introduction.
The yarn apparently proves itself successful, gaining a full 30 cents from the introductory price of 19 cents. The yarn was touted for suits, coats, dresses, sweaters and afghans. Lees Minerva published a number of misses clothing / accessory patterns through the 30's, so I'd assume several included patterns calling for this yarn.
In 1943, Lees Minerva published pattern book - Minerva Afghans - Vol 66 which featured the Milady Yarn in each pattern. These patterns are in the shop, should you be interested in looking.
During World War II, sale advertisements dwindled in newspapers, which leads me to assume manufacturing may have been discontinued early 1940's as wool supply to common market became scarce.
There was a brief marketing sprint at the end of the 1940's, ending in 1951, which I assume, was final sell-off of the product line. The pattern featured in this advertisement is Charleston Block - a colorful classic Granny.
And ... that's all I know. But, should I come across other books or information about this yarn, I'll update this post. If you should happen to know more, I'd appreciate your sharing!