A critical survey of early Church history, the works of the Church Fathers and several councils of the Church reveals a consistent call for unity. Heresies, politic intrigue and struggles for governance have aggravated attempts to remain in the union. The insistence on unity and the persistence of the Church to unify reveals an ontological reality. While our knowledge of the Church can be given in epistemological terms, looking at the Church to discover its essence, what it means to be church, opens a different way of encountering the Church and, eventually, understanding the nature of the Church to be one. The transformations in the early Church as it spread to new cultures, the impact on the Church at the founding of “New Rome” by the Emperor Constantine, the changes brought about when Constantinople fell to the Ottomans in 1453 and the resulting birth of the Renaissance in the West with the beginning of the autocephaly Church in Russia and subsequent reunions, are especially rich in manifestations of unification among dissidence. This paper will focus on these particular moments. The concept of looking at the essence of the Church exposes us to an understanding of what the Church is as a universal presence. Stating that the Church has no physical dimension, that it is a unique congregation abiding solely by an actual historic document or defined only by written doctrines does not show us its full essence. Likewise, seeing the Church as defined by how it differs from another, exists in objection to another church or how it avoids affiliation with others, reveals a body that does not have a unifying essence and is lifeless. Looking closer at its essence as it is revealed over time, shows us a living Church that has repeatedly manifested unification as its particularly unique identity. This paper is a reflective look of the Church through the ages which presents to us a look into the essence of the Church. Primary and secondary sources are critically examined with an emphasis on ontological manifestations. The moments in history that are presented in this paper are especially revealing of the unifying nature of the Church in various settings. This paper has limitations though. While the deliberate historic selections may give extraneous interpretations, it is intended to reveal previously under-estimated treasures, and this topic will require being given greater context in any expanded study. / Christian Spirituality, Church History and Missiology / D. Th. (Church History)