Ecclesiastical history, for a Latter-day Saint, must include the Great Apostasy—otherwise, there is no need for prophetic Restoration of the Christian Gospel through Joseph Smith. Apostasy, in Mormon ecclesiastical history, is a repeated phenomenon whereby the Church of God falls away from doctrinal purity and loses priesthood authority. Latter-day Saints see a scriptural pattern of apostasy and restoration in the Bible and interpret Abraham, Moses, Josiah and some other Old Testament prophets as men called of God to restore His truth to His people. In the Christian era, Latter-day Saints similarly read apostasy in to the New Testament narrative and Patristic period; typically asserting the loss of Apostolic authority and the resulting doctrinal impurity. Historically, Latter-day Saint theology surrounding the Great Apostasy, the apostasy which occurred between the death of the Apostles and the Restoration under Joseph Smith, has emphasised its roots in medieval Roman Catholic practices and celebrated Protestantism as a forerunner of the Reformation. The Church has since distanced itself from Protestant narrative and accordingly it is time to re-interpret Mormon theologies of the Great Apostasy.
The theology of the Great Apostasy is deeply connected to Restoration, or the divine revelations to Joseph Smith, which resulted in doctrinal purity and Apostolic authority. Among the significant claims of the Restoration are: the correction of certain doctrinal errors, additional scripture, that Apostolic Succession is vital to the integrity of the Church and its Sacraments, that Apostolic authority had disappeared from all Christian Churches and required restoration, and the importance of continuous and direct revelation between God and the successors to the Apostles. Simply put, for these claims to have relevance, the Great Apostasy must have involved the loss of doctrinal purity, Apostolic authority, and direct revelation between God and His Church. Mormon theologians have routinely attempted to locate the historical instant where the apostasy overtook Christianity; however, interesting those these attempts have been, they are problematic because A) Latter-day Saints are not Donatists and do not believe that Sacraments are invalidated through the sin of a priesthood holder and B) Latter-day Saint claims of Apostolic Succession are mirrored by other Churches with historically demonstrable claims to Apostolic Succession—like the Roman Catholic, Eastern Orthodox, and Anglican Churches.
A possible solution to the above problems can be found in the Book of Mormon account of Alma the Elder, a priest who brought about a restoration to his people and reformed the ancient Nephite Church. According to this narrative, Alma was a Nephite priest—perhaps ordained during a period of apostasy or who had apostatised. Upon hearing from the prophet Abinadi, Alma realised the extent of his own wickedness and the wickedness of the Nephite Church under King Noah. A political threat to the established Church, Alma went into exile and began preaching to his people and restoring them to doctrinal purity, received renewed authority from God, and offering legitimate Sacraments—like baptism. The Nephite Church and its priests, in the days of Alma, had apostatised and did not conform to the necessary patterns ordained of God for His Church. The priests taught against the coming of the Messiah, they practised simony, did not keep nor teach God’s commandments, and denigrated scriptural authority. However, these priests had ostensibly been ordained by legitimate priests and some of them may even have been taught the correct doctrines and practices. Alma’s restoration, a restoration of people to doctrinal purity, apostolic authority, and authorised Sacraments was significant because it restored doctrinal and sacramental authority; but not priesthood authority which had never completely vanished.
If the Great Apostasy can be understood in a similar manner; or, in other words, if the Joseph Smith received the fullness of Apostolic authority from Peter—not because the priesthood was completely wiped from the Earth but in order to restore the prophetic and apostolic offices, doctrinal purity, and sacramental orthodoxy, then Mormon ecclesiastical historians can move beyond searching Christian history for the exact instant of apostasy; instead acknowledging the last two-thousand years of Christian heritage. Doctrine and Covenants Section 1 states that the apostasy was not about lost priesthood keys but because
“they [the other Christian Churches] have strayed from mine ordinances, and have broken mine everlasting covenant; they seek not the Lord to establish his righteousness, but every man walketh in his own way, and after the image of his own god, whose image is in the likeness of the world, and whose substance is that of an idol, which waxeth old and shall perish in Babylon, even Babylon the great, which shall fall.”
This position does not diminish the Restoration, nor does it lessen the claims of the Church to complete and full Apostolic Succession, doctrinal purity, and sacramental authority. Joseph Smith was still ordained by St Peter, by the laying-on of hands, as an Apostle. He still restored legitimate doctrines and Sacraments which had been lost. The Church of Jesus Christ of Latter-day Saints is still the true, universal, and living Church of Christ. The benefits of this reading of the Great Apostasy are further opportunities for ecumenism and the eventual reconciliation of all churches with the Universal Church of Christ, the Church of Jesus Christ of Latter-day Saints, and increased reliance upon Apostolic authority as vested in the Prophet and the Quorum of the Twelve.
 Recently the LDS Church has distanced itself from the following texts, especially Mormon Doctrine, which was seen as problematic even at the time of its publication in 1958; however for a detailed dialogue on LDS theologies and ecclesiastical history of the Great Apostasy see: James E. Talmage, The Great Apostasy (Salt Lake City: Deseret News, 1909); Brigham Henry Roberts, Outlines of Ecclesiastical History (Salt Lake City: George Q. Cannon & Sons, 1893); Bruce R. McConkie, Mormon Doctrine: A Compendium of the Gospel (Bookcraft, 1958).
 Doctrine and Covenants, 1:15-16.