The Timing of the Apostasy

The apostasy has long been thought of as a gradual loss of truth; even in the Bible it is translated as a "falling away". This does a disservice to the word, as it is actually a rebellion against authority. From the very first, when Jesus taught the Jews, there was an element that plotted against him, rebelling at his authority. It culminated in his crucifixion and death. His resurrection caused quite a stir; and the apostles spread the news of his resurrection through their missionary work. The church enjoyed tremendous growth. The church grew too fast; the rising number of converts were unschooled in the knowledge of the gospel and also brought many preconceptions with them. It was all the apostles could do to stem the tide of heresies. Meanwhile, the church suffered significant persecution. Other religions found the Christian missionaries invasive, and a threat to their own ideologies. Jews were sent throughout the land to spread propaganda against the Christians, accusing them of all sorts of crimes. Many members of the Christian church left the church, rebelling against the authority of the apostles, and returning to their old ways.

Some started churches of their own. Greek philosophy was popular at the time, and many of these startup churches taught a mixture of Christianity and Greek philosophy. Some ministers even started asking to be supported by the members, defying the instructions of the apostles. It is known to historians as the Hellenization of Christianity. Many students of the universities of philosophy joined the branches of Christianity, and applied their philosophies to the scriptures. In later centuries the concept of the Trinity would be adopted in the language of philosophy.

The timing of the restoration of the Lord's church in 1830 isn't a coincidence. Several prominent theologians believed that there would be a restoration of God's kingdom in that year. They based their opinions on certain bible prophecies in the books of Daniel and Revelations.
In Revelations, chapter 12, John tells us about a vision which he saw. In this vision, a women, wearing a crown of twelve stars, gives birth to a manchild who would eventually rule all nations. The women escapes to the wilderness, where she stays for 1260 days. The Hebrew YOM, here translated as days, can also be translated as years. In at least two other places in the Bible, years are represented as days. In the Joseph Smith Translation of the Bible, aka the Inspired Version, "days" is changed to "years". Joseph wasn't alone in his calculations: many Christian scholars also believed that this represented years. The women represented the Lord's church, and the fleeing to the desert represented an escape from the wickedness of society. It isn't when the apostasy or rebellion started, but it is when the apostasy ended, Satan having won his victory, the church being removed from the earthf
For various reasons, the starting year of the apostasy has been pegged at 570 AD. Prominent theologians and scholars John Calvin, Adam Clarke, William Ward and Edward Elliot all believed that the apostasy started in 570 AD. During this year, three major events took place. The Lombards, a Germanic tribe, invaded Rome. The Papalcy was created. Mohammad was born. All three have been accused of being the "antichrist.postasy literally means rebellion. There seem to be different phases of rebellion. The first phase is the rejection of prophets and apostles. Then comes the loss of plain and precious doctrines, and the adoption of heresies. Finally, the church is turned to doing the work of the devil, enslaving men and making war. My own theory also uses this same year as the start of the apostasy, but for a different reason. In the Doctrine and Covenants, Joseph Smith recorded the following revelation:

"36 That the rights of the priesthood are inseparably connected with the powers of heaven, and that the powers of heaven cannot be controlled nor handled only upon the principles of righteousness

37 That they may be conferred upon us, it is true; but when we undertake to cover our sins, or to gratify our pride, our vain ambition, or to exercise control or dominion or compulsion upon the souls of the children of men, in any degree of unrighteousness, behold, the heavens withdraw themselves; the Spirit of the Lord is grieved; and when it is withdrawn, Amen to the priesthood or the authority of that man."

(Doctrine and Covenants 121)

In 570 AD, the Catholic church started inforcing religion by the sword. That is when, in my opinion, that the last vestige of priesthood authority was lost. I don't know whether that last vestige of priesthood authority resided in the Catholic church, or whether it resided in another church that was persecuted into extinction, but either way, it lends support to the date of the start of the apostasy.
The following quote is from Trevan G. Hatch, in his book Visions, Manifestations and Miracles of the Restoration.
"In the past three years, I conducted extensive research concerning eighteenth and nineteenth-century predictions regarding the conclusion of the 1260-year apostasy... I read hundreds of predictions about the restoration and can confidently state that an overwhelming majority of eighteenth and nineteenth-century Christians believed that some kind of a restoration would commense in the nineteenth century."