The reader must be reminded here of a few salient facts in the religious history of the seventeenth century. All these undercurrents of heterodox thought, with but few and soon repressed public manifestations of its presence, were obscured by the massive movement in Church and State. During the Commonwealth the episcopal system was abolished, and a presbyterian system substituted, though with difficulty and at best imperfectly. After the Restoration of Charles II the Act of Uniformity re-established episcopacy in a form made of set purpose as unacceptable to the Puritans as possible. Thereupon arose the rivalry of Conformist and Nonconformist which has ever since existed in England. Severely repressive measures were tried, but failed to extinguish Nonconformity; it stood irreconcilable outside the establishment. There were distinct varieties in its ranks. The Presbyterians, once largely dominant, were gradually overtaken numerically by the Independents. Perhaps it is better to say that, in the circumstances of exclusion in which both were situated, and the impossibility of maintaining a Presbyterian order and organization, the dividing line between these two bodies of Nonconformists naturally faded out. There was little, if anything, to keep them apart on the score of doctrine; and in time the Presbyterians certainly exhibited something of the tendency to variety of opinion which had always marked the Independents. Besides these bodies, the Baptists and Quakers stand out amid the sects comprised in Nonconformity. In both of these there were distinct signs of Anti-trinitarianism from time to time; as to the former, indeed, along with the earlier Baptist movements in England and on the Continent (especially in the Netherlands) there had always gone a streak of heresy alarming to the authorities. Among the Quakers, William Penn is specially notable in connection with our subject. In 1668 he was imprisoned for publishing _The Sandy Foundation Shaken_, in which Sabellian views were advocated. It need hardly be pointed out that among the still more eccentric movements, if the term be allowed, heterodoxy as to the Trinity was easy to trace.