The A-line was first introduced by Christian Dior in 1955, but the style was too extreme a departure from the tiny waist, full skirt dresses of the decade and the 50’s weren’t ready to adjust to a more natural body shape.
It would take a few years - as well as a couple of inches off the sides - to appeal to the body-conscious ladies who had worked hard for their womanly figures (always with the help of severe girdles and bullet bras).
Dior’s slimmer A-line became a more acceptable and flattering shift in dress style, ushering in the transition to the flat, willow-like silhouette of the decade.
The A-line was actually a slight variation of the popular straight shift dress released by Balenciaga in 1954. Its name was derived from its letter A shape, with the two sides gently angling out from the bustline to create a slightly wider hem.
These shift dress differed greatly from the tiny, nipped-in waists of the early decade, but all it took was one very influential citizen to change cultural tastes.
In the days of the Kennedy White House, Jackie was the United States’ unofficial fashion maven, and she favoured straight style shifts over the more extreme waists. The First Lady adopted the A-line shift for her personal style, popularising the dress as worn with her trademark pillbox hat, gloves, and handbag for the epitome of class.
Mrs. Kennedy's change to the A-line shift silently told women that no longer would they need to be constricted by the impossible shapes that necessitated a girdle.