The year 1690 saw the appearance in Holland of an anonymous octavo volume entitled Opuscula philosophica. The second of the three opuscula it contained was entitled Principia philosophiae antiquissimae et recentissimae. Two years later, an English translation of this work was published, with the title The Principles of the Most Ancient and Modern Philosophy: Concerning God, Christ, and the Creature; that is, concerning Spirit and Matter in General. The preface to the book explains that it was a translation by one ‘J. C.’ of ‘a little treatise published since the Author's Death’, originally published in Latin in Amsterdam. No author is named, but the address to the reader explains that it ‘was written not many Years ago, by a certain English countess, a Woman learned beyond her Sex’. The Latin edition, of which this is a translation, gives no further clues as to the identity of this erudite Countess, but her authorship treatise was not altogether a secret in the early Enlightenment. In his biography (1710) of Henry More, Richard Ward prints the preface originally prepared for publication with this treatise, and gives an account of its author, ‘the Lady Viscountess Conway’, whom he describes as the ‘Heroine pupil’ of the Cambridge Platonist, Henry More (1614–87). The unpublished preface speaks of her ‘singular Quickness and Apprehensiveness of Understanding’ and her ‘marvellous Sagacity and Prudence in any Affairs of Moment’.