Some “thought” the church, the one and only church Christ instituted, went off the rails in the 16th century and so martin Luther tried to place what “seemed” to be off the rails, back on the rails.
What actually occurred, was that the Church and Her teachings were spot on, and some of the members of the clergy were abusing their power.
Martin Luther then started his own man made sect of religion, calling it Christianity, and things really went awry after that, beginning division after division and brand new doctrines brought about by the false doctrines of sola scriptura and sola fide.
The results are very evident, in that now what was once one, as Christ called it to be, is split into almost 40,000 divisions, all thinking their individual way of interpreting scripture is somehow correct, except that it is contrary and different to everyone else’s theology.
So I would say that what appeared to be the church in 1521 under the guise of Luther and Calvin and Wesley and Zwingli, wnet off the rails at that time and has never ceased. The Church christ established still remains, with the teachings still intact.
I do not know of a Lutheran, Presbyterian or any other church that hld to the teachings of their founder since the reformation period.