Box Coat was first popular in
1940s
The box coat or half coat is arguably one of the most iconic styles of the 1940s and 50s. It hung very wide and straight, much like the shape of a box. They either hit at the bottom of a woman’s hips or went all the way to mid-shin. The 1950s versions often had a fuller shape than the 1940s box coats. Large pleats at the back shoulder line created a swing coat meets box coat look. Collars, pockets, and button were large. Most came in solid colors: ivory/cream, black, blue, red or brown. The only popular pattern was checks.
Source:http://vintagedancer.com/1950s/history-1950s-coats-jackets/
