The thesis examines the relationship between Newman's treatment of early Church heresies and his contemporary situation in the period up to 1845.Part I traces his view of heresy from the early Trinitarianism of its evangelical period and snows now It became a rhetorical tool in his defence of the Established Church, 1828-31, culminating in The Arians of the Fourth Century. His continuing use of analogies between Arianlsm and contemporary controversy is traced between 1832 and 1837, before an examination of the relation between rhetoric and politics in the years of Emancipation, Repeal and Reform (1829-32), and in the changed situation after 1832. Part II illustrates the use Newman made of his study of Sabellianism and Apollinarianism Ian Ism to describe 'liberalism', which he argued to be a heresy developing into an underlying Infidelity. His rhetoric was provoked by R.D.Hampden's view of Tests, and influenced by the example of his friend Blanco White's embracing of Unitarian ism in 1835. Newman's consideration, under the category 'Sabetlian', of a variety of systematic theologians arose out of a need to universalize Oxford controversies into an argument about 'rationalism' (Tract 73). He extended his critique both to aspects of Nicholas Wiseman's Roman Catholic apologetic, and, in his strictures upon H.H.Milman, to liberal Anglican historiography. Part III shows Newman's own past-present analogies turning Inwards upon himself in a parallel between his "Via Media' and Monophysltism. The relation of this analogy to his later reminiscences and to the revolution in his concept of orthodoxy and heresy in The Essay on Development, is considered. The modification of his general understanding of heresy, in the light of his new-found idea of development, is then related to his rhetorical use of specific heresies. The Conclusion assesses more theoretically the implications of Newman's rhetorlclzation of Antiquity and considers If there Is a fundamental coherence to his heresiology during the Anglican period.