The events that led to the Salem witch trials began shortly after the First Doctor and his companions first arrived in Salem in what they at first thought was 1691, but was in fact 1692. Hoping to escape the hysteria which they knew was about to envelope the settlement, the Doctor, Ian Chesterton, Barbara Wright, and Susan Foreman made a hasty retreat back to the TARDIS, but were followed by Rev. Parris, who was suspicious of these new arrivals. It was while tracking the time travellers in the nearby woods that Parris caught his daughter and niece with some other local girls engaging in black magic rituals. Parris's daughter and niece accused Tituba, a slave who was living with the family as a servant, of bewitching them. Parris beat her and compelled her to confess herself a witch. The delusion thus commenced lasted 16 months, concluding with the Salem witch trials.
When the TARDIS crew returned to Salem after the start of the hysteria, Parris held Susan prisoner in his home for two weeks, forcing her to testify along with the other girls against many innocent people, including Rebecca Nurse and John and Elizabeth Proctor, condemning them to the gallows. Only when the Doctor threatened to expose Parris as the cause of the fits and convulsions afflicting the girls did he relent and allow the time travellers to leave. However, the damage had been done. Over twenty people would die by the time the witch hunt ended in January 1693. (PROSE: The Witch Hunters)