Might cognitive impairment, being an ‘idiot’, disqualify you from ‘belonging’ as a Quaker, in an age before membership? What was idiocy in seventeenth-century terms and, as the Age of Reason dawned, where would the idiot have stood among Friends? These and other questions come to mind from study of a case in the Court of Chancery in the early 1680s. It concerned land and property in Glamorgan and the son of a notable dissenter. The case brings into fresh focus some well-known seventeenth-century Quaker names, filling gaps in the known biography about them. Above all, it sheds light on an individual about whom Friends’ records are silent, though he was part of a family of Quaker activists.