Did You Know: Cartes de visite or CDVs, miniature portraits used as calling cards, were extremely popular during the American Civil War. These photographic calling cards, approximately 2½ x 4 inches in size, had been invented in France in the early 1850s, and their popularity quickly spread throughout Europe and eventually to the United States, where the corollary development of the photograph album spurred a collecting craze in the 1860s that became known as Cartomania. In addition to assembling albums of family photographs, the public sought to collect images of celebrities and views of favorite places and sites.