The modern Spiritualist movement traces its founding to 1848, when sisters Kate and Margaret Fox, teenagers in Hydesville, New York, reported communicating with a spirit through a series of rapping sounds, a phenomenon that quickly attracted wide public attention and, within a few years, produced a rapidly growing movement of individuals claiming similar mediumistic abilities across the United States and, soon after, Britain and continental Europe. Mediumship as it developed through the following decades took varied forms, including trance mediumship, in which a medium claimed to allow a spirit to speak or write through them while in an altered state, physical mediumship, involving claimed physical phenomena such as table movement, materialization or ectoplasm produced during a seance, and mental mediumship, involving claimed clairvoyant or clairaudient communication without physical manifestation.
Spiritualism grew rapidly in the nineteenth century partly through its resonance with contemporary interest in scientific investigation of previously unexplained phenomena, and partly, particularly following the mass bereavement of the American Civil War and later the First World War, through its promise of continued communication with deceased loved ones, a promise that gave the movement particular appeal during periods of widespread grief.