Development of doctrine is one of the fundamental principles in Catholic theology. It encapsulates the idea of hermeneutical continuity in the official teachings of the Catholic Church, whose mission is to faithfully transmit the contents of divine Revelation in history. As such, the principle of doctrinal development casts an important light on the theological understanding of Revelation, Tradition and the Church. The category of doctrinal development was introduced into modern Catholic scholarship by the celebrated work of John Henry Newman, An Essay on the Development of Christian Doctrine (1845, 1846, 1878). In this work, Newman employed the epistemology of a developing idea: the identity of revealed truth is preserved in the historical growth of understanding. His presentation of doctrinal development was based on the analogy between the process of a development of religious understanding in the individual mind and the doctrinal development in the Church as a whole. For Newman, the idea of the Church as a living and organic subject of development endowed with infallibility has implications for ecclesial structure: most importantly, it absolutely requires a central authority in the Church, the papacy, for effective exercise of the universal teaching office in the Church. It is less known that a work on the development of doctrine was also written by the Russian religious philosopher, Vladimir Sergeevich Soloviev. His 1886 treatise Dogmatic Development of the Church in Relation to the Question of the Reunification of the Churches defends the Catholic understanding of the development of doctrine against the dogmatic conservatism of some Russian Orthodox theologians. In his treatise, Soloviev employed an epistemology of development very similar to that of Newman, in which the identity of an idea is manifest in the organic process of historical development. His presentation of doctrinal development was based on the pneumatological principle of unanimity in the Church, which manifests a special divine-human subject of development in the universal Church. In his subsequent work, La Russie et l'Église Universelle (1889), Soloviev elaborated his findings from the treatise on doctrinal development in a powerful apologetic of the papal primacy in the Church. This dissertation investigates the background, the origin and the presentation of doctrinal development in Newman and Soloviev0́9s theological works. This comparative study is focused especially on the connection between the development of doctrine and the papal office in the thought of both men. Newman and Soloviev's converging theories of doctrinal development are explored primarily in their original proposition of ecclesiological foundations for the papal primacy in the Church. The insights from the study of Newman and Soloviev0́9s ecclesiological ideas are then related to more recent developments in ecumenism, particularly as regards the relationship between eucharistic and universal ecclesiologies.