The costume balls of the early twentieth century have a fascinating history. Originating with the the masquerade balls (bal masqué) of the 15th century, the custom of wearing a costume or disguise of some sort to celebrate special occasions has long been a part of cultures throughout the world.
By the 18th century, the European craze for masquerades was set, but the licentious behavior so often a part of the masquerade caused them to fall out of favor by the beginning of the 19th century. Masks were discarded, and the emphasis upon costume of an elevated nature developed into the fancy dress balls of the Victorian age. The American counterpart was the costume ball, which enjoyed great popularity among the well-to-do of this country during the the Gilded Age and forward.
Edith and Harold McCormick were certainly no exception to this popular type of event. Young, extremely wealthy and married (1895), they attended many events - right up until the eve of Edith's departure for Switzerland and her 8 year stretch as a patent and student of Carl Jung.
The photo of Edith shown above was published in many copies of the Chicago Tribune that I have among Edwin Krenn's papers. It remains one of my favorite images of her, as it is rather uncharacteristic of her usual luxe yet staid style. (As seen in the 1907 picture at the top.) Given the rather exotic nature of her costume, and the fact that it was published in many papers after her death in 1932, I'd be curious to know her thoughts about being recollected in such an avant garde fashion .