The church I grew up in — the Worldwide Church of God — taught what we were told is a unique view of church history. The true gospel had been perverted soon after Jesus’ death and all the Christianity we see around us is false Christianity. They explained it similarly to this:
Following the death of Jesus Christ, wicked people persecuted and killed many Church members, and other Church members drifted from the principles taught by Jesus Christ and His Apostles?. The Apostles were killed and the priesthood authority-including the keys to direct and receive revelation? for the Church-was taken from the earth ( 2 Thessalonians 2:1-3). Because the Church was no longer led by priesthood authority and revelation, error crept into Church teachings. Good people and much truth remained, but the gospel? as established by Jesus Christ was lost, resulting in a period called the Great Apostasy.
Trouble is, this is also how the Church of Latter Day Saints explain church history (full document here).
How can there be two “only true churches”?
If only there were only two groups claiming to be the only true Christians…