The history of Arianism by M. Maimbourg; shewing its influence upon civil affairs: and the causes of the dissolution of the Roman empire. To which are added, two introductory discourses, I. Concerning the Nature of Error in Doctrines merely Speculative, shewing, that the Belief of such Doctrines may be required of us as necessary Terms of Salvation; wherein also the case of positive Institutions is particularly considered. II. Shewing that the Doctrine of the Trinity is not merely Speculative. with an appendix Containing an Account of the English Writers in the Socinian and Arian Controversies. By William Webster , M. A. Curate of St. Dunstans in the West.