James Nayler was perhaps the most articulate theologian and political spokesman of the earliest Quaker movement. He was part of a West Yorkshire group of radicals who added revolutionary impetus to George Fox’s apocalyptic preaching of Christ’s coming in the bodies of common men and women. With other Quaker leaders, Nayler insisted upon disestablishment of the Church, abolition of tithes, and disenfranchisement of the clergy, in order that Christ might rule in England, through human conscience. For early Friends, Christ’s sovereignty in the conscience was less a principle of individual freedom to dissociate religiously than a basis for collective practices of revolutionary worship, moral reform, social equality, and economic justice. All these were features of the nonviolent struggle Nayler called the ‘Lamb’s War’. His meteoric career is outlined in this study, a movement from apocalyptic prophet, to stigmatised Christ-figure, to withdrawn quietist.