A long rectangular shawl or wrap, very often red with a decorative border in portraits, was also worn, and was lain around the midriff when seated—for which sprawling semi-recumbent postures were favored.
In France the style was sometimes called "à la grecque" after the decorations found on the pottery and sculpture of Classical Greek art, though the empire dress had multiple sources, including Marie Antoinette's chemise à la reine, a simple white gown influenced by those worn by European women living abroad in warm climates, including the Americas.
The change is probably partially due to the French political upheavals after 1789 (which encouraged the recovery of ancient virtues, and discouraged the type of ostentatious ornately luxurious display formerly common in aristocratic fashions).
The early styles often featured entirely bare arms, as in the ancient exemplars, but from about 1800 short sleeves became more typical, initially sometimes transparent as in David's Portrait of Madame Récamier (1800), then puffed.
The style was very often worn in white to denote a high social status (especially in its earlier years); only women solidly belonging to what in England was known as the "genteel" classes could afford to wear the pale, easily soiled garments of the era.